section_path: Course/Ming Great Wall
section_name: Ming Great Wall
paragraph_text: Ming Great Wall
  
  The Jiayu Pass, located in Gansu province, is the western terminus of the Ming Great Wall. From Jiayu Pass the wall travels discontinuously down the Hexi Corridor and into the deserts of Ningxia, where it enters the western edge of the Yellow River loop at Yinchuan. Here the first major walls erected during the Ming dynasty cut through the Ordos Desert to the eastern edge of the Yellow River loop. There at Piantou Pass (t 偏 頭 關, s 偏 头 关, Piāntóuguān) in Xinzhou, Shanxi province, the Great Wall splits in two with the "Outer Great Wall" (t 外 長城, s 外 长城, Wài Chǎngchéng) extending along the Inner Mongolia border with Shanxi into Hebei province, and the "Inner Great Wall" (t 內 長城, s 內 长城, Nèi Chǎngchéng) running southeast from Piantou Pass for some 400 km (250 mi), passing through important passes like the Pingxing Pass and Yanmen Pass before joining the Outer Great Wall at Sihaiye (四海 冶, Sìhǎiyě), in Beijing's Yanqing County.
  
  The sections of the Great Wall around Beijing municipality are especially famous: they were frequently renovated and are regularly visited by tourists today. The Badaling Great Wall near Zhangjiakou is the most famous stretch of the wall, for this was the first section to be opened to the public in the People's Republic of China, as well as the showpiece stretch for foreign dignitaries. The Badaling Great Wall saw nearly 10 million visitors in 2018, and in 2019, a daily limit of 65,000 visitors was instated. South of Badaling is the Juyong Pass; when it was used by the Chinese to protect their land, this section of the wall had many guards to defend the capital Beijing. Made of stone and bricks from the hills, this portion of the Great Wall is 7.8 m (25 ft 7 in) high and 5 m (16 ft 5 in) wide.
  
  One of the most striking sections of the Ming Great Wall is where it climbs extremely steep slopes in Jinshanling. There it runs 11 km (7 mi) long, ranges from 5 to 8 m (16 ft 5 in to 26 ft 3 in) in height, and 6 m (19 ft 8 in) across the bottom, narrowing up to 5 m (16 ft 5 in) across the top. Wangjing Lou (t 望 京 樓, s 望 京 楼, Wàngjīng Lóu) is one of Jinshanling's 67 watchtowers, 980 m (3,220 ft) above sea level. Southeast of Jinshanling is the Mutianyu Great Wall which winds along lofty, cragged mountains from the southeast to the northwest for 2.25 km (1.40 mi). It is connected with Juyongguan Pass to the west and Gubeikou to the east. This section was one of the first to be renovated following the turmoil of the Cultural Revolution.
  
  At the edge of the Bohai Gulf is Shanhai Pass, considered the traditional end of the Great Wall and the "First Pass Under Heaven ". The part of the wall inside Shanhai Pass that meets the sea is named the "Old Dragon Head". 3 km (2 mi) north of Shanhai Pass is Jiaoshan Great Wall (t 焦山 長城, s 焦 山 长城, Jiāoshān Chángchéng), the site of the first mountain of the Great Wall. 15 km (9 mi) northeast from Shanhaiguan is Jiumenkou (t 九 門 口, s 九 门 口, Jiǔménkǒu), which is the only portion of the wall that was built as a bridge.
  
  In 2009, 180 km of previously unknown sections of the Ming wall concealed by hills, trenches and rivers were discovered with the help of infrared range finders and GPS devices. In March and April 2015, nine sections with a total length of more than 10 km (6 mi), believed to be part of the Great Wall, were discovered along the border of Ningxia autonomous region and Gansu province.