There is also a west pit in the Shanshan Guild Hall in my hometown, and I didn't know its function until later.

  I heard that there was water in the Forbidden City because of the rainstorm.

  I think of my hometown Shanshan Guild Hall in Shedian Town, Sheqi County, Henan Province.

  Shanshan Guild Hall was built with donations from merchants in Shanxi and Shaanxi during the Qing Dynasty. It was a place where merchants gathered and offered sacrifices to Guan Gong. It took 70 years from construction to completion, and the inscription "Dragon" and "Tiger" of Empress Dowager Cixi is still impressive.

  Shanshan Guild Hall has no wood, no stone and no carving. Its stone carving and wood carving are praised by archaeologists as "the best in the world", and even the Forbidden City is willing to admit defeat.

  About 200 meters to the west of Shanshan Guild Hall, there is a big pit. Shoppers commonly call it "Xida Pit" or "Xiaoxihu Lake", with an area of about 3,000 square meters. There is water in the pit, which is full but not overflowing, and it is not satisfied with the heavy rain. It turns out that there is a back channel in the pit, which leads directly to the river outside the city.

  According to the elders, the West Pit was formed by borrowing soil from the Shanshan Guild Hall, which shows that the engineering quantity is huge.

  A few years ago, due to real estate development, the west pit was filled up and shops were built on it.

  At that time, two uncles who had been in Zhengzhou for many years were very angry when they heard about it, and said that they should not fill the west pit.

  Although the Shanshan Guild Hall is located in a depression, it has rained heavily for hundreds of years, and there has never been water accumulation. However, in the summer when the Xida pit was filled, a rainstorm flooded the Shanshan Guild Hall.

  Only then did people know that there was a dark channel under the guild hall leading directly to the west pit.

  In ancient times, no matter big cities or small cities, there were open channels and back channels, which drained invisibly. Nowadays, most of the drainage systems are copied from abroad, and there are always waterlogging floods in cities every rainy season, so reference must be combined with reality.