Beijing Underground City was built in 1969 as a civil air defence fortification. The underground city project, which lasted ten years, was completed in 1979. It is divided into three defensive fortification districts and leads to all directions of the urban area, forming a preliminary scale of civil air defense tunnel network.
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投稿:2017年9月11日
M12***47
5/5とても素晴らしい
原文に戻す
It's OK. It's beautiful. It's a little boring. You have to come back and have a look.