It is no easy task to determine what makes a city modern or not. What makes the difference with mere economical attraction today? Is it eco-friendliness, housing quality, traffic fluidity, or communication network density?

One can hardly take part for one specific criterion when it comes to urban modernity. However, some cities throughout the world do stand out because they manage to take up special challenges with the use of latest technologies. What if New York, London, Tokyo or Paris were not the leading edge of urban modernity anymore? With astronomic house prices, almost permanent traffic jams and pollution as well as rampant unemployment and insecurity, the world's richest cities remain crucial pieces of the global economy but they also acknowledge unquestionable weaknesses.

Elsewhere in the world, some younger cities have anticipated and tackled problems that other metropolitan areas of the world have too much lately considered and... now struggle to cope with. Those rising metropolis often belong to the so-called "emergent" world and are not often spoken of. But they undoubtedly deserve to be called modern because of their success in carefully integrating their environment and taking advantage of it.

Among the most recently developed city, Singapore stands for one of the fastest growing and most economically sturdy place in Asia. Back in 1965 when it became independent, Singapore would not be different from the bulk of developing countries and cities at that time. But the city took advantage of its waterfront and geographical situation on the border of Indian and Pacific oceans so as to develop its harbor. Singapore harbor now stands for a cutting edge facility, being the second most important fret harbor in Asia and having been the first harbor in the world for containers till 2010. This little state-city thus managed to reach standards of living and education that are comparable to those of the most developed countries.

Following quite the same path, Hong Kong Island has got to be a main fret Asian harbor as well as one of the first stock market of Asia and the 6th of the world. Hong Kong takes advantage of its geography as well as its history. The city was under British domination before it was conveyed back to China. It has therefore kept the economic and judiciary system inherited from colonial era. As a matter of fact, this heritage contributed to make Hong Kong a highly globalized city, enjoying living standards and attracting foreign investments by far more important than those in the rest of continental China. As cities, Singapore and Hong Kong have both achieved economically. But this is not the only mark of a modern city: architecture and urban planning are also undoubted factors.

In this regard, the cities of Brasilia and Curitiba in Brazil appeared to be the most innovative. Brasilia was designed by Oscar Niemeyer and Lucio Costa at the end of the 50's. At that time, Brazilian President Juscelino Kibtschek choose those two architects to build a modern city with efficient transportation and communication network, open and natural spaces as well as neighborhoods with specific functions. The result of this plan is a clear city which outer and inner borders are traced by large roads. The latest efficiently serves each of the autonomous residential neighborhoods with their own shops, schools, and natural spaces as well as the business and administrative districts that compose Brasilia.

Curitiba is another example of Brazilian success in urban planning. In this southern city, up to three quarters of the population use the excellent common transportation city service. In spite of its enormous population -- estimated around 3,5 million of people -- Curitiba managed to reach one of the best levels of education, security and quality of life in a country that remains deeply marked by poverty and violence. Far away from Carioca favelas, Curitiba is commonly nicknamed the model-city of Latin America; an expression that paradoxically highlights both the urban successes and failures of Brazil.

The definition of urban modernity surely includes ecology too. The ability of a city to function without overexploiting natural resources and respecting the environments is a crucial stake for contemporary urban areas. Freiburg im Breisgau, in Germany, has made tremendous steps towards these standards. In the late nineties, the city built entire sustainable neighborhoods and thus earned to be known as an eco-city. In Freiburg in Breisgau, Vauban and Riesefeld neighborhood are exclusively composed of solar powered "passive-houses" -- meaning houses that are highly energy efficient and needs very low amounts of energy to run --. In those neighborhoods, car traffic is also submitted to special restriction such as a generalized 5km/h speed limit. Thus, the whole life of Vauban and Riesefeld is organized to reduce the ecological footprint of those neighborhoods.

In terms of ecology, the water topic is another crucial point to determine the modernity of a city. In this regard, many cities in the Middle East especially deserve to be pointed out. Some of them increase their efforts to preserve and use this rare and vital resource as cleverly as they can. For instance Doha, Qatar's capital city has a particularly active water policy coupled with a dynamic urban planning. Indeed, Doha is a flourishing city: whole modern neighborhoods have been erected and dedicated to education (Education City), housing (The Pearl, Al Waab) and business. To cope with its arid climate, Doha also recycles most of its wastewater. Be it coming from house or industrial activities, wastewater is treated and reuse in different purposes. Well, sewer water of Doha West is entirely treated and recycled for farm irrigation.

As for industrial effluents, Pearl GTL plant's water treatment system is a telling example of the top edge technology Qatar is able to afford in order to optimize its water resources. Actually designed by Veolia Water especially for Shell's purpose in Qatar, this system has caught the attention of the whole country as well as the world engineering community. Pearl GTL recycles twelve different kinds of effluents and turns them into 5 different types of water that are reused in by the plant later on. This unique system enables Pearl GTL not to waste a single drop of water. It therefore stands for the most water efficient petrochemical plant in the world and Qatar will undoubtedly become an inspiration for future models of water efficient cities.

Definition of urban modernity can be debated and such a concept continuously evolves. Cities like New York and London used to be widely accepted representations of modernity because of their tremendous economic, politic and cultural achievement. However, newly developed cities are nowadays competing with historic leaders and tend to promote new standards of living and modernity: the openness to the world, the quality of the urban planning, the ability to use advanced technology to respect the environment... and many others. Cities like Singapore, Curitiba or Doha do illustrate how rich the characteristics of a modern city could be. Nevertheless, one of them seems to be commonly shared: modern cities take advantage of their environment but also simultaneously try not to damage it. This characteristic is most definitely the starting point of a modern urban model.