Shanhaiguan or Shanhai Pass (literally, "Mountain and Sea Pass") is a part of the city of Qinhuangdao, in Hebei province, People's Republic of China. In 1961, Shanhaiguan became a site of China First Class National Cultural Site. Along with Jiayuguan and Juyongguan, it is one of the major passes of the Great Wall of China.
It is a popular tourist destination, featuring the eastern end of the Great Wall. The "First Pass Under Heaven" is also a noticeable tourist attraction. The place where the wall itself meets the Pacific Ocean (at the Bohai Sea) has been nicknamed the "Old Dragon's Head."
Shanhaiguan is located south of Yan Mountain, and north of Bohai. For centuries, the pass guarded the narrow passage between the Northeast and the Central East region of China. Both Northern Qi Dynasty and Tang Dynasty constructed passes. In 1381, Ming general Xu Da constructed Shanhaiguan, named due to its position between mountain and the sea.
Later Ming general Qi Jiguang began fortification and construction of a military city around Shanhaiguan, building cities and forts to the east, south and north of the pass. Shanhaiguan became one of the most heavily fortified pass in China, and to this day, it is also one of the best preserved passes in the Great Wall.
During the end of Ming Dynasty, Shanhaiguan general Wu Sangui was about to surrender and join the rebel forces of Li Zicheng when he heard that his concubine Chen Yuanyuan was taken by Li Zicheng. Enraged, he contacted the Qing and the leader Dorgon. Afterwards, Wu Sangui opened the gates of Shanhaiguan for Qing soldiers and together fought a decisive battle against Li Zicheng. The victory by the Qing Dynasty hastened the foundering of Li Zicheng's political powers and firmly established Qing as the dominant power in China.
During the Qing Dynasty, Shanhaiguan, situated between Shenyang and Beijing, was referred to as the Key to the Capitals. Both during the Republic, as well as Eight-Nation Alliance and Second World War, Shanhaiguan was the site of many conflicts.
All four sides of Shanhaiguan had a gate: Zhendong (East), Ying'en (West), Wangyang (South), and Weiyuan (North). Due to disrepair over the centuries, only Zhendong gate still remains today. Zhendong Gate is the most important gate in Shanhaiguan due to its position, which faces outside the pass. Written on a board that hangs above the gate is an alternate name of Shanhai Pass, "First Pass Under the Heaven" (天下第一关). This should not be confused with the "First and Greatest Pass Under Heaven" (天下第一雄关), a different pass located at the west end of the Great Wall.