6. The Far East : Japan, Singapore and China

In China, the city of Beijing (Peking) developed extensive networks of underground bomb shelters long before it built its first metro line. Some of these have been rehabilitated for social use (restaurants, etc.). While Beijing and Shanghai are flat cities, many others are hilly, sometimes with steep slopes; rail and road tunnels are not uncommon, as are, more recently, under-river tunnels. The city of Chongqing used its underground quarries and bomb shelters (during the war against Japan in 1940) as a source of summer air-conditioning for public buildings, including cinemas. The city's School of Architecture has extensively studied the problems of the underground environment, in particular the dehumidification of tropical air (to avoid water condensing on the "cold wall" of the cavities).

Japan's major cities, which have developed extensive metro networks, have...