Simatai (Chinese: 司馬台) is a section of the Great Wall of China located in the north of Miyun (密雲) County, 120 km northeast of Beijing, holds the access to Gubeikou (古北口), a strategic pass in the eastern part of the Great Wall.
The slopes around Simatai are extremely barren, it is said that this place used to be densely covered by forest, but the military removed the plantations to avoid being used by the enemies as covers.
The section was originally built during the Northern Qi dynasty (550–577) and rebuilt during the Hongwu (洪武) Emperor's reign during the Ming dynasty (14th century).
Simatai is well preserved, some of the bricks are covered with beautiful patterns or even inscriptions.
One sided wall (單邊牆) is one of the features Simatai, it is a segment of wall which is as thin as 40 centimeters wide, since the mountain ridge here is too steep and narrow to build the normal Great Wall.
Hanging precariously onto the mountains, Simatai is known for its steepness. Open-air gondolas provide a way to ascend partway up the wall.
