Located in Gubeikou Town northeast of Miyun County, the Simatai Great Wall stretches from Wangjing Tower in the east to Houchuankou Pass in the west. It has 35 beacon towers in all. Divided into eastern and western parts by the Mandarin Duck Lake, the Simatai Great Wall is celebrated for its steepness, uniqueness and good condition. It was included on the World Heritage List in 1987.