China - 2005
The Great Wall of China was built in sections beginning in the 7th century BC during the Warring Period in Chinese history. They were connected under Emperor Qin Shihuang in the period 220-206 BC to fend off normadic invasions from the north. It measures 5,500 miles long, 16 feet wide, and 16 to 26 feet in height. In comparison, the driving distance between New York and San Francisco is 2,900 miles.