Great Wall of China

Famously one of the only manmade structures to be seen from space, the Great Wall was originally constructed as a defensive measure against tribes of the north and northwest, over thousands of years, causing many deaths and much suffering. The architecture can be divided into different sections, such as fortressed town, castle, garrison city, mountain pass city, stronghold city, city wall, watch tower, wall tower and furnace mound (for making smoke as signal on sight of invasion). These architectures are connected and coordinate with each other, forming a complete network of defensive strategy, divided into three parts: Mountain Pass City, Beacon Fire Site and Wall. The Chinese call it the Wall of 10,000 Li (10,000 being the highest number in Chinese philosophy), and it’s often referred to as a dragon: a protective and sacred symbol in China. The great Chinggiz (Genghis) Khan was one of the only leaders to successfully take his armies straight through its fortifications.