Life in modern cities truly causes a lot of nuisances. In the first place, citizens have to deal with traffic congestion every day. This problem is even worse in the rush hour when so many people run out to work and are stuck on streets for hours. Next, high cost of living is also a serious issue in the city, especially in metropolitan cities. More and more people find it difficult to live on their modest salaries when prices are going up all the time. Financial pressure makes city dwellers become constantly stressed and tired. Finally, the polluted air caused by exhaust emissions from millions of vehicles, construction dust and the lack of green trees negatively affects residents’ health. Many people suffer from respiratory problems such as cough, sore throat or asthma. Indeed, city life brings a number of difficulties as well as challenges to its citizens.