人口在不断的向大城市聚集，土地越来越宝贵，促使大城市的建筑不断向高处发展，从美国的摩天大楼，到上海的世贸大厦，新的高度不断被挑战，犹如一颗颗参天大树，城市森林，由钢筋混泥土构成，人们由如困兽在其中。
The population is constantly gathering in the big cities, and the land is becoming more and more precious, which promotes the buildings in the big cities to develop higher. From the skyscrapers in the United States to the world trade center in Shanghai, the new heights are constantly challenged, like towering trees. The urban forest is composed of reinforced concrete, and people are trapped like animals
