Why is Houhai in Beijing called "sea"?

This is because Houhai is an integral part of Shichahai, which is connected with the waters of Zhongnanhai.

Shichahai includes three waters: Qianhai, Houhai, Xihai (also known as Jishuitan) and its adjacent areas. It echoes the "first three seas" at a distance, so it is commonly known as "the last three lakes".

Houhai is one of the basic projects planned and designed by Yuan Dynasty in13rd century. This is an idle place with water, and you can see mountains and weeping willows.

Houhai East starts from Di 'anmenwai Street, reaches Xinjiekou Street in the west, Ping 'an Street in the south and Second Ring Road in the north, with a total area of 146.7 hectares, including 34 hectares of water area and 1 1.5 hectares of green land. This is the ancient waters of the Yuan Dynasty in Beijing 700 years ago.

Extended data:

Houhai is located in the center of Beijing, only four or five stops away from Tiananmen Square, connected with the famous Beihai Yishui, far away from Jingshan and the Forbidden City.

It is said that the water in Houhai is connected with Long Mai in the Forbidden City, which has been a treasure trove of geomantic omen since ancient times. As a result, eminent monks built temples here, while princes and ministers chose to build houses and make gardens on the shore. Celebrities moved to the lake one after another and started their initial waterfront life in Houhai. Therefore, as the saying goes, "Shichahai comes first, then Beijing".

Houhai is a good place to learn about culture, history, customs and characteristics.

Baidu Encyclopedia-Houhai (Lake Scenic Area, Xicheng District, Beijing)