Keywords

These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

2.1 The Uniqueness of Cities

Cities are distinguished from other human settlements by two key features: they constitute dense and large clusters of people living and working together, and they are the focus of myriad internal and external flows. This is what makes cities uniquely active and vibrant places that are always more cosmopolitan than culturally uniform. Historically these features are expressed in different ways over millennial time as new modes of working and living in cities are generated and diffused. In this chapter these changes are sketched out from the earliest beginnings of urbanization to cities in contemporary globalization.

We begin by exploring when and why cities emerged, and how urbanization today has come to shape life across the entire planet as part of globalization. Looking at the beginnings of the very earliest cities reveals how the genesis of urbanization and the external relations of cities are indelibly intertwined. We will describe how these external relations—links with other cities and with other places—played a crucial role in the creation of the first cities, and also stimulated wider processes of change shaping human history, such as the development of agriculture.

The unique dynamism of cities has enabled them gradually and then rapidly to grow in number and size. Today the flows and networks originating in and circulating through cities are a crucial part of processes of globalization and cities now play a central role in shaping economies and social life worldwide.

2.2 When Did Cities Begin?

An idea which is essential to any understanding of cities is “civilization.” We can define this as referring to societies which are spread across relatively large areas of the globe and which have achieved high levels of social and political interdependence. Cities and civilizations are indelibly linked: cities are nodes which connect many different places together, enabling large-scale interdependence. Additionally, they are the major locales of social change where new forms of working and housing are continually invented and reinvented to create new dynamic and expansive worlds of human activity. Thus cities, through their unique connections, sizes and densities, provide opportunities for people to innovate and adapt their living, always in relationship with many other places.

Initially seven “pristine” (i.e., independently developed) civilizations were recognized in Western scholarship, namely, Mesopotamia (in today’s Iraq), Egypt, the Indus Valley (in today’s Pakistan), China, Central America and the Central Andes (in today’s Peru). Over time, a strongly western-centric perspective in scholarship quite wrongly imagined a trajectory of “civilization” and urbanization stretching over time from Mesopotamia/Egypt through Greece and Rome, culminating in what was seen as the most important civilization, that of modern Europe and America. Perhaps this stemmed from the way in which Europeans at this time saw themselves as uniquely “civilized” compared to other societies. But this intellectual interpretation of the trajectory of cities in time (limited to the last 5000 years) and space (focused on the West) has become increasingly contested as our understanding of early urbanization has progressed through modern scholarship. Instead, we find that many more civilizations existed much earlier in historical time, organized through interconnected cities; and that by far the most significant and long lasting groupings of cities in history were those centred on China.

Initially the identification of early cities and civilizations was based upon excavation of places with large-scale urban monumental remains, notably in Mesopotamia and Egypt. It was the grand urban architectures of the old civilizations that had particularly impressed scholars, but it is becoming increasingly apparent that they had multiple forebears—earlier urban places that developed as regional groups of cities in many different parts of the world. These cities emerged from nodes in successful trading networks where existing traders’ camps took on work in secondary production—converting previously traded raw materials (e.g. silicon rock) into manufactured goods (e.g. silicon blades)—and in the tertiary activities this generated (e.g. logistic services such as organization and storage). Where these new arrangements generated increased demand, transitory trading camps grew into concentrations of specifically urban activities that we can identify as the earliest cities.

Although small—the most studied such settlement, Çatalhörük (in modern Turkey) dating from around 9000 years ago, had a population of about 5000Footnote 1—these urban places represented an epochal change in communications, opportunities and innovation. Compared to previous hunter-gatherer bands of about 150 people, new concentrations of people of this size generated many more social interactions, both within the settlement and through external links. By means of materials processing and trading, such people working in and through interconnected regional groups of small cities created new economic systems.

Such very early cities have been difficult in practice to find. Not only were they without monumental architecture, their buildings, especially ordinary housing, would most probably have been made of materials such as mud and wattle, and these have not survived, especially in wetter regions. Finding urban remains in these circumstances is largely a matter of serendipity: a classic case is Japan’s Sannai-Maruyama settlement (Jomon culture) dating back 5500 years with more than a thousand buildings; it was only found during the digging of foundations for a new baseball stadium (see Box 2.1). However, archaeologists using new airborne laser scanning technology are finding new networks of ancient cities in places such as Amazonia and Cambodia as well as uncovering extensions of known networks in places such as Egypt.

Box 2.1 Making early cities

Cities were not invented as a complete urban package. The small city that features most in the debates on early urbanization, Çatalhörük (in Anatolia, Turkey, some 9000 years ago), illustrates this well: it had no streets! In this settlement, houses abutted each other and ladders were essential to movement between houses within the city. Ladders enabled entrance to houses through holes in their roofs for people travelling across the urban space created by the combined roofs. The invention of streets to replace ladders as more convenient means of urban movement was to come later.

That there was no simple blueprint for inventing cities is shown in African indigenous urbanization in the Middle Niger region (West Africa possibly more than 3000 years ago). Here the layout was the opposite of Çatalhörük; it was an urban complex with large open expanses up to 200 m wide between a central cluster of buildings and surrounding smaller clusters. Its similarity to Çatalhörük is in its concentrating people in new original formats thereby enhancing inter-personal communication and opportunities for innovation.

Initially, the Middle Niger settlement complexes were not considered to be “urban” not only because of their unusual structure but also because the indigenous people were assumed not to be capable of something as sophisticated as city-building. Such sentiments were to be found with other early city sites: Great Zimbabwe and associated settlements in southern Africa (c. AD 1300), early Mayan cities (in Central America c. 300 BC), and Cahokia (Mississippian culture c. AD 1100) were all examples of urbanization denied because local non-European peoples were not considered feasible city-makers by Europeans although all are now studied as candidates for early urban process.

Today, searches for early signs of urbanization are among the most exciting research developments in urban studies. In particular, evidence is mounting, including from remote sensing, that the dense tropical forests Europeans encountered in their exploration of the world may not be pristine nature as originally and continually thought. In particular, the Amazon forest may have housed a large urban civilization, including a city “fourteen miles long” on the banks Amazon river, and similar claims are being made for the forests of Congo and South East Asia.

2.3 The Emergence of Large Cities

The multiple beginnings of early cities in regional groups around the world included what we today would consider to be quite small cities with population estimates of only a few thousand; much larger cities are found later in traditionally recognized civilizations (see Box 2.2). And size does matter: the larger the city, the more social interactions and therefore the greater the chances for generating innovations. Thus, although Mesopotamia’s cities are no longer seen as being the first cities, they do constitute the first network that incorporates large cities. For instance, about 5000 years ago Uruk in Sumer (lower Mesopotamia) had a population estimated at 80,000. This counts as a truly new world of working and housing; think again of the logistics involved. Just the daily feeding and disposing of the waste of this number of people was a massive undertaking. It is when cities reach this size that evidence about their form and functions (including their innovations) becomes increasingly available. In Uruk’s case these include the crucial twin inventions of accounting and writing; the new profession of scribes is an archetypal urban occupation group.

Box 2.2 Making the first large cities

Early cities relied upon creating a hinterland where the development of agriculture satisfied the new demand of food. But these first cities proved not to be resilient: their rudimentary agriculture put heavy demands on the soil. To keep up with a growing urban population, agricultural production gradually moved further and further from the city. At some point transport of food to the city became too difficult to maintain. Thus early cities appear to last several generations but are then abandoned leaving their erstwhile hinterland as waste land, sometimes referred to as an ‘empty quarter’ reflecting its desolation.

To create large cities required a new way of providing food: sustainable agriculture to enable resilient cities. The solution was irrigation agriculture based upon controlling flooding that continually replenished the soil. Thus the first large cities are associated with the great traditional civilizations are on the lower reaches of major river systems—the Tigris-Euphrates in Mesopotamia (Iraq), the Nile in Egypt, the Indus in Pakistan and the Yellow (Hang Ho) and Yangtze rivers in China. Of course these river systems also facilitated trade—water transport was much more efficient than land transport before modern industrialization. Hence there was a coming together of two requirements for a massive new phase or urbanization: trade generating economic spurts and sustainable productive agriculture.

Subsequently these civilizations became dominated by new imperial political structures wherein the largest cities were capital cities, politically favoured by tribute rather than economically favoured by trade. Economic generation of the largest cities only returned with the onset of modernity after 1500.

Although Uruk is the largest city in early Mesopotamia it should be seen as part of a Sumerian network of cities, specifically eleven cities with a total population of over a quarter of a million. It is such great extensions of urbanization that created what were considered the initial civilizations. Similar spurts of large city growth occurred in Egypt, China and India perhaps slightly later, and later still in the Americas and sub-Saharan Africa. In this way cities became an established part of human history exhibiting continuity to the present. Two urban trajectories were of special importance, namely, a “West” trajectory combining Mesopotamia and Egypt (and covering western Asia, Mediterranean/Europe), and an “East” trajectory centred on China (also including Korea and Japan). Between them these two regions constituted the nine biggest city networks before 1800 (i.e. prior to modern industrialization). Each of these networks had ten or more cities with populations over 80,000 within a two hundred-year period (Table 2.1). Here we find a very clear challenge to the traditional West-centric narrative concerning the history of urbanization, for it is the dominance of Chinese networks of cities that stands out. Note that five (the majority) of these very large city networks are found in the East compared to the West. More importantly, the East trajectory shows a growth in size and numbers of cities over time in a single, broad regional grouping whereas there was no such coherence in the historical urbanizations of the West. Put simply, it is only in East Asia that we find an historical development encompassing a strong and continuous urban pattern.

Table 2.1 The nine largest historical city networksa

Why, then, is there such a strong traditional emphasis on the role of the West in the study of large-scale historical urbanization? We would argue that this is the result of the modern West as the dominant region of the modern era bringing its own forebears to the front in writing world histories. Correcting this basic geographical misunderstanding is crucial for two reasons. Historically, we would expect the Chinese as inhabitants of the region of great cities to be the most innovative (see Box 2.3). From a contemporary standpoint, global understanding of China’s long urban tradition is necessary for placing China’s great current urban revival in a broader perspective.

Box 2.3 Innovations from the cities of China before 1800

As the centre of the world region with a continuous trajectory of city networks over millennia, it is to be expected that China should be the locale for urban innovations par excellence. And this is indeed the case. Joseph Needham, the great scholar of China in the mid-20th century, catalogued 262 “inventions and discoveries” and some of the more important that were converted into practical innovations are listed below:

Abacus; Acupuncture; Anemometer; Axial rudder; Ball bearings; Belt drive; Blast furnace; Callipers; Cartographic grids; Cast iron; Chain drive; Chess; Crossbow; Decimal place; Dominoes; Drawloom; Firecrackers; Flamethrower; Folding chairs; Gear wheels; Gunpowder; Harness; Hodometer; Hygrometer; Iron-chain suspension bridge; Kite; Lacquer; Magnetic compass; Mouth organs; Multiple spindle frame; Oil lamps; Paper; Planispheres; Playing cards; Porcelain; Pound-lock canal gates; Printing; Relief maps; Rotary fan; Spindle wheel; Steel production; Stirrup; Stringed instruments; Toothbrush; Trip hammers; Weather vane; Wheelbarrow; Winnowing machine; Zoetrope.

This is a very impressive list and raises the question as to why China was not the region to create a global urbanization. In fact China never came close to such an outcome, remaining a traditional empire until incorporated into the western economic sphere in the 19th century. As a traditional empire, tribute from a large and productive peasantry was the main source of wealth for a political elite so that, despite the large sizes of traditional Chinese cities they remained demographically a minority.

But focusing on these two major urban developmental trajectories neglects other parts of the world that did not have so many large cities but nevertheless did create some very large urban centres of their own. Historical demographers identify 63 very large cities (i.e. cities with over 150,000 inhabitants) before 1800. Of these, 17 reached the impressive size of half a million inhabitants—they are large cities even by present day standards. All these cities are mapped and named in Fig. 2.1 where the continuity of cities, their resilience, is also shown in their durability over time—cities marked by the darkest circles are those which have been more consistently present over time. Again, it should be remembered that the cities that are mapped represent only the largest cities in the urban groupings with many more cities below the size threshold, including many important but smaller urban settlements in regions not included in the map (notably in the Americas). Many of the cities named on Fig. 2.1 are well-known (e.g. Constantinople, today’s Istanbul) but there is a large number that do not have wide recognition today. For instance, about five hundred years ago, VijayanagaraFootnote 2 was larger than Constantinople and was probably the second largest city in the world at that time. Therefore the key point of the map is to show the sheer extent of large-scale urbanization before modern industrialization.

Fig. 2.1
figure 1

Cities with populations estimated over 150,000 before 1800

But let us now draw your attention to the bottom section of Table 2.1. The story told through large city populations now veers in a new direction. There is a profound transformation in the urban process in terms of both urban scale and geography after 1800 that signals a broader societal change. This is the modernity invented in the West based upon capitalism where economic factors dominate to the benefit of cities. Thus the growth of very large cities in Europe and the Americas in the 19th century is not the outcome of a long historical ‘Western’ trajectory of urbanization as traditionally argued; rather it represents a disruption, a new modern trajectory that leads to contemporary globalization.

By the end of the 19th century all networks of cities were incorporated into a single world system. In this new modern world the number of large cities and their total populations are at a completely different level compared to previous large city networks. And it is the West (now including the USA) that is conspicuously the terrain of the new large cities. This change represents the key urban growth phase of the process that has culminated in the 21st century’s status as the first “urban century.” What caused this shift? The answer lies in the significant changes that took place in the relationships between cities and their wider environments, especially the political structures of states and empires.

Before the modern era, the world’s population was overwhelmingly rural; even in the most urbanized regions, city populations largely remained below 10 % of the total. In this rural world, the largest cities were the capital cities of world empires. The dominant activities in these cities revolved around political control and administration together with servicing the needs of the political elites. Tribute brought from across the empire supported large urban populations. In these traditional empires there was also an urban hierarchy consisting of inter-related cities, provincial political centres and economic centres of trade and production.

In China, self-ascribed as the “Middle Kingdom”, the capital city at the centre of urban networks changed with the dynasties but the rest of the urban system was stable over time. In the West, the great capital cities of early Empires, i.e. Rome and Baghdad, persisted over time and were huge centres of consumption, but they were far apart in time and space. Neither of these cities was to be part of the early modern city network of the West, which gradually emerged after 1500 (Table 2.1). In fact, the most dynamic areas of this early modern network were in northwest Europe, centred on Amsterdam, so it was towards the edge of the traditional urban networks of the “civilized” world of the West that this important new urban network emerged (see Fig. 2.1). As a new trajectory, it had a much smaller overall population relative to the other established historical networks (Table 2.1), making it appear to be an unlikely starting point for the unprecedented growth that the West experienced under industrial modernity after 1800.

To understand this radical shift in the scale and geography of modern urbanization from the long pre-modern history, we once again find ourselves thinking about how the course of history has been profoundly shaped by the dynamic nature of cities, especially their capacity to stimulate innovations and foster external relations.

2.4 Urban Take off: Modern Cities in Globalizations

The solution to the puzzle as to why the most important modern urban developments emerged in one of the previously lesser urbanized areas of the globe, is to be found in the political context of early modern cities rather than in their demography. Not being part of an overarching empire meant generally that there was no need for large political centres, which explains the initially smaller size of the cities in the early modern Europe (Table 2.1). But this also meant that the relative autonomy of these cities was enhanced. Without an overarching traditional empire, political authority was divided into multiple territorial states. And, crucially, this fragmentation of political power changed the relations between political and economic elites. In traditional empires political elites had dominated the commercial classes; in the new modern cities, this situation changed into a much more balanced relation between political and economic forces. New relations between cities and states came into being, giving more autonomy to cities, and leading to the intensification of their dynamic role as centres of innovation. With cities as innovation hubs under reduced political restraint, the outcome has been a speeding up of social change, the hallmark of modernity. Thus, the regional clusters of centres of economic innovation that have changed our world, developed in urban conditions which were relatively independent of political power. Innovation in these centers has been above all reflexively related to their underlying economic dynamics. The following are the three main regional clusters of modern economic innovations.

First, the Dutch cities were the great early modern centres of commercial innovation in the 17th century and operated in a loose political structure, the “United Provinces”, that was arguably not a fully formed state, or if so, was a “merchant’s state” where the political elite exercised only limited power.

Second, in the late 18th and early 19th centuries, the great wave of innovations underlying what we call the Industrial Revolution originated in the towns and cities of northern Britain, far removed from the political centre of London.

Third, the rise of the USA as an economic power in the late 19th century came as a consequence of innovations in the cities of the Manufacturing Belt stretching from New England to the Midwest, within a weak federal state when Washington, DC was still a small city of minor significance.

These three urban powerhouses of modernity each relied on extensive external connections, growing through plunder and trade (including the Atlantic trade in slaves) and through colonial (territorial) and commercial (market) expansions. Their dynamism accelerated economic development in new uneven geographies then emerging and leading to the globalized world familiar to us today. As the first of these economic powerhouses, Dutch cities had a key regional effect on urbanization, leading the shift of urban economic growth from Mediterranean Europe to north Atlantic Europe. This had subsequent global ramifications but was not itself fully global. However, the other two powerhouses, focused on cities in the UK and the USA, were the sites of immense urban growth (as indicated by the data for 1900 in Table 2.1). In this new world-making process of urbanization we can identify three related but distinctive phases of globalization, as a result of worldwide economic inter-connections.

2.4.1 Imperial Globalization

This first globalization came to its fruition some time around 1900, though its influence was still being strongly felt over the first half of the 20th century. The founder of modern geopolitics Halford Mackinder referred to it as “global closure.” Imperial globalization derived from the political process whereby the world was carved up into competing sea empires of European states (and latterly involving the USA and Japan). Economically this process operated worldwide—forming the original or “old international division of labour”—where colonies, ex-colonies (Latin America), and countries subject to unequal treaties (economic opening via political pressure, notably in China) supplied food and raw materials for European markets. This stimulated the emergence of three types of fast-growing cities: (a) the new imperial capitals in Europe, the largest being London and Paris; (b) industrial cities in Europe, the largest being Manchester and the Rhine-Ruhr urban region; and (c) dependent cities beyond Europe dealing with the logistics of relaying products to Europe and coordinating emerging regional economies, the largest being Buenos Aires, Shanghai and Calcutta (Kolkata). A parallel regional structure also developed in North America where New York functioned as the business and commercial capital complemented by industrial cities in the Manufacturing Belt (such as Chicago, Cleveland and Pittsburgh) and local supply cities in the West (Denver, San Francisco), and the South (Atlanta, Dallas).

2.4.2 American Globalization

This form of globalization grew in the first half of the 20th century out of the regional arrangements just described above. New York became the world’s leading financial centre. At the same time, a burgeoning mass production system in North America and Europe was complemented by the development of mass consumption. Increased productivity translated into higher wages so that levels of consumption soared in what J.K. Galbraith in the 1950s famously referred to as the “affluent society.” Across US cities, suburbia became the primary landscape of this new world of consumption, epitomized by the case of Los Angeles. Americanization is the term used to describe the diffusion of this way of living beyond the USA. It encompassed Western Europe over the “long post-war boom” after 1950, and then spread to middle classes across the world including the erstwhile Second World of communist countries late in the century. The shopping mall came to symbolize modern cities in the American mode across the world. In addition, an important political change affected much of the world: the post-1945 era was also a time when many former colonies became independent countries. In seeking to promote their own national development paths these countries created new political economies increasingly centred on their capital cities. Hence, most countries in what came to be called the “Third World” in the Cold War political climate of the time developed “primate city” urbanization with one city becoming very much larger than the rest. The corresponding nationalist agendas in these countries, while fostering new manufacturing concentrations and civic investment, ironically neglected urban development beyond the capital. Instead, territorial policies in hinterland areas displayed a strong commitment to rural development, especially in Africa and Asia. The extreme case of this kind of policy is represented by China, where urbanization actually declined in the 1960s.

2.4.3 Corporate Globalization

The current situation is one that can best be described in terms of corporate globalization. This represents a progression of Americanization but is increasingly shaped by other centres of economic influence, notably in Asia. The main agents of the previous globalization were US multinational firms with highly developed export capabilities. Then, through the 1970s, the newly emerging communications and computer industries started to herald a new world of near instantaneous flows of information worldwide. Corporations were thus increasingly able to operate as complex global entities, a shift that greatly facilitated the relocation of industrial production to cities in poorer countries so as to take advantage of cheap labour. This development was complemented by states pursuing neoliberal, free-market oriented policies thus opening up national economies to global economic competition and enabling corporations to invest widely in different countries. These corporations came to be characterized as transnational, and then, more simply, global corporations. US firms represent the main instances of these economic goliaths but they are now joined by firms from many other countries, including China. In the latter case a rigorous export growth policy initially based upon cheap labour resulted in the largest rural-urban migration flow in history, more than 100 million people between 1990 and 2005. The majority of China’s population is now urban. The outcome of these overall trends has been a highly integrated world economy undergirding what urban sociologist Manuel Castells has termed a global network society. Castells identifies global cities and a broader world city network as a spatial organization challenging traditional international relations of states in the 21st century.

From Mackinder’s political global closure to today’s world of transnational corporations, these three globalizations represent a sequence of overlapping processes with the earlier phases not disappearing but fading into the later, so that all are present in contemporary corporate globalization.

2.5 Global Urbanization Inside Out

Historically, urbanization has been closely associated with economic growth, and cities have typically been the main motors of this growth. The usual result is that the richest countries characteristically had the largest cities But this is not always the case today (Table 2.2; see also Box 2.4). This reversal is clearly shown in Table 2.3. In the development of imperial globalization in the half-century up to 1900 the fastest growing cities were European and US industrial cities and capital cities, plus a few key ports located in the rest of the world. In the development of American globalization in the next half-century this general pattern continued but with a clear tendency for US cities to eclipse their European counterparts. However with the advent of corporate globalization in the second half of the 20th century this pattern has been completely reversed. The fastest growing cities in this period are not found in the regions of economic dominance. Rather, of the 25 cities in this period listed in Table 2.3, seven are from South Asia, five from Latin America, four from the Middle East, and three each from East Asia and Sub-Saharan Africa. Only three of these cities are located in the USA, and two of these, Miami and Dallas, are ranked at the bottom of the list in 23rd and 25th places, respectively.

Table 2.2 Today’s largest cities (termed Megacities)
Table 2.3 Fastest growing cities, 1850–1900, 1900–1950 and 1950–2000a

Box 2.4 Megacities

The United Nations Human Settlements Programme (UN-Habitat) is concerned with urban problems—shelter, waste disposal, traffic, air pollution, water supply—emanating from growth of very large cities. This organization uses the term “megacity” to describe the largest cities in the world; originally focusing on cities with populations above 8 million, now the threshold is 10 million. Table 2.2 shows the 35 cities that qualify in 2016. The population estimates are for “urban agglomerations,” broadly densely integrated city regions, rather than “metropolitan areas” based upon administrative units. The former are favoured because they represent the actual urban geography of the cities rather than their political designation. The table shows cities of amazing sizes: five over 25 million with Guangzhou approaching 50 million. For most of these cities the rise to “mega” status has been relatively recent (Table 2.3). Thus, compared with the eight cities from the richer countries of the world economy (Europe, USA, Japan), the other 27 cities are critically struggling to cope with the challenges of their recent rapid expansion in size with far fewer material resources. China is a special case: the five cities featured in the table are the tip of an iceberg reflecting the largest rural-urban migration ever recorded. Although residents of these poorer megacities face many problems, we should not underemphasize the opportunities that are also offered. These huge agglomerations of people are a maelstrom of ideas, inventions and innovations for survival, adaptation, advancement, cooperation and much else in all realms of human activity, not least in creating jobs and shelter. Whether these social interactions are largely organized through formal or informal arrangements, legal or illegal in relation to government regulations, it is in megacities and other very large cities that people will be forging an urban future in the 21st century.

The current situation, then, is one characterized preeminently by a world-wide network of major urban centres. Some have been termed, “megacities”, by reason of their large populations typically in the multiple millions (see Box 2.4). More generally, “world cities” (also called “global cities”) can be identified by their functions in integrating the world economy—their deep insertion into global capitalism and their significant role in shaping global economic and social processes. Although many of the most prominent of these cities are located in the economically dominant economies of the Global North, increasingly cities in East and South Asia and elsewhere are playing a significant role in globalization processes. We should also recognize that a plethora of smaller urban centres beyond the mega- and global/world cities exist across the entire globe; these also play an important role in global economic and social processes and some of them are marked by exceptionally rapid recent growth.

The following two chapters now explore how it is that cities both shape and are shaped by the array of broad processes we have discussed so far, focusing on two of the most significant elements of life in cities, namely, making a living and finding shelter. It is only after basic needs in regard to work and home are satisfied that citizens can fully partake in wider aspects of city life. In the end, this form of life lies at the core of the future of the planet, socially, economically, politically, and culturally, for it is in cities that the most advanced and innovative trends of social change are concentrated.