A lot of countries have started to make a change in the organisation of urban areas, in order to head towards sustainable way of life in the cities. Singapore for example puts into practice the concept of plant-covered architecture on the city buildings, which have at the top of their roofs some kind of farming plants. There is also the city of Detroit, Michigan (USA) which focuses on « create a high-quality, accessible, attractive, and environmentally sustainable city environment while reducing resource use and reversing negative environmental impacts ».
According to me, a lot of people are willing to make some changes in their city, such as creation of car park at borders of the city in order to favour more sustainable transports (tram line, bicycle grids, car free areas).
I think that the best way to reach a realistic sustainable city is to find the right balance between the functions of the city and the elements that make it possible to respond to contemporary issues in the fields of energy, transport, etc. To me, a city in which nature is increasingly incorporated and which seeks to put the well-being of its citizens by putting respect for the environment ahead of economic returns is a city that has the capacity to be sustainable (and quite futuristic don't you think ?).