世界上的大城市都面临着非常严重的交通问题。一方面城市中现有的道路不足以使交通保持顺畅,另一方面,城市里也没有足够的空地建新的道路。为了加快进入和穿行城市的速度,城市规划者建造了地下铁路系统。市民和观光者从众多车站中的一个加入这个隧道管网,在地下,他们迅速地抵达目的地,然后从地下“冒出来”进入阳光下,就像鼹鼠从鼹鼠丘里爬出来。地铁看起来像是一项现代发明,实际上,地铁最早诞生于146年前的英国伦敦 The big cities in the world are facing very serious traffic problems. On the one hand, the existing roads in cities are not enough to keep traffic flowing smoothly. On the other hand, there are not enough vacant areas in cities to build new roads. In order to speed up the speed of entering and traveling through the city, city planners built a system of underground railways. Citizens and sightseers join the tunnel network from one of many stations, underground, they quickly reach their destination and then “pop” out of the ground into the sun, just as the mole climbs from the Mole come out. Subway looks like a modern invention, in fact, the earliest subway was born 146 years ago in London, England