7. City inside Mountain山中之城
Picture above is the lost city in Petra, Jordan. Built with a perfect defense against external attacks and sand storms. Very impressive, considering that this city was built in ancient times when the machine is not created yet.
上图显示的是约旦失落之城--皮特拉。由于建在山中,这座城市能有效地防御外部袭击和沙尘暴。想想在当时还没有机械的时期能建成这样的城市,这是多么的不可思议。