A citizen of a city needs a place to live, a place to work (a job) and other several places to get services and to relax in order to get new energy for living and working further. This is the life circle, the “perpetuum mobile” of a human being.

A lot of the cities of the world seem to continue to attract more and more people, to have more and more inhabitants and to grow. 50 % of the global population lives in cities. All the cities of the planet have together a surface not bigger than 2% of the surface of the planet. So, half of the population of the planet lives only on 2% of its surface. This means pressure, growing pressure, and this pressure should be well managed for a better future for all.

On the other hand, the climate change or the wars, the terrorist threats, their consequences – refugees, migrants, represent another pressure on our planet and risk of its destabilization.

So we need to change continuously our mentality in order to educate the same approach on the behalf of each of us for the city like we have for our own home: to consume less energy and to have more “green” solutions, to keep it clean. Than a sustainable city needs to have a solid infrastructure, to have an urban planning that allows the city to breath, to develop a comfortable transport network including the metropolitan area, to have proper services: education, healthcare, social security, to have green areas and leisure zones, to have attractions for visitors etc.

Our generation, and each generation later, should have in mind that we have not received the city as a gift from our predecessors, but that we have the responsibility to prepare the city for the next and next generations.

May be like that we could help our cities to be a “perpetuum mobile” for the human beings.