Great Wall of China
The Great Wall of China is a barrier fortification in northern China running west-to-east 13,171 miles (21,196 km) from the Jiayuguan Pass (in the west) to the Hushan Mountains in Liaoning Province in the east, ending at the Bohai Gulf. It crosses eleven provinces/municipalities (or ten, according to some authorities) and two autonomous regions (Inner Mongolia and Ningxia). Construction of the wall began in the Qin Dynasty (221-206 BCE) under the First Emperor Shi Huangdi (r. 221-210 BCE) and continued over hundreds of years throughout many different dynasties.