Longest wall
Who
Great Wall of China
What
3460 kilometre(s)
Where
China Shanhaiguan,Gulf of Bohai

The Great Wall of China is the longest in the world and has a main-line length of 3,460 km (2,150 miles - nearly three times the length of Britain - plus 3,530 km (2,193 miles) of branches and spurs. Construction of the wall began during the reign of Qin Shi Huangdi (sometimes spelled Qin Shihuangdi or Qin Shi Huangdi, 221-210BC). Its height varies from 4.5 to 12 m (15 to 39 ft) and it is up to 9.8 m (32 ft) thick. It runs from Shanhaiguan, on the Gulf of Bohai, to Yumenguan and Yangguan and was kept in repair up to the 16th century. Some 51.5 km (32 miles)of the wall have been destroyed since 1966, and part of the wall was blown up to make way for a dam in July 1979.