Nowadays big metropolises and big cities develop and keep growing with a great speed. The inhabitants observe how new buildings, business center, parking places that are full of cars appearing every day in different parts of the city. Unfortunately the amount of green parks with trees in metropolises decreases with great speed as well. Such situation is very dangerous and extremely sad. If people do not change their attitude towards this problem it will definitely lead to quite unpleasant and even very dangerous results and circumstances. Greenery is very important element in maintain a good health of people. People need lots of oxygen to breathe in and they take it from trees. Nowadays in big cities such as at the following City Houses ppt template people breath in toxic elements which are waste products produces by cars, plants, factories and so on. Waste products spoil the nature, environment and our ecology.