Secret nuclear bomb-proof steel door at Beijing subway station

During the Cold War, Beijing's subway stations served as bomb shelters to protect the city's residents from nuclear attacks, according toPopular Mechanics.

Many train stations are equipped with heavy steel doors designed to provide people with safe shelter from a large explosion. These doors are cleverly camouflaged within the station walls, making it impossible for people to detect their presence or the government's nuclear war preparations.

The photo went viral on Chinese social media.A recent photo shows a thick steel plate extending from floor to ceiling between the wall of Chongwenmen station in Beijing and another steel plate lying on the station floor.

According to experts, these steel plates that do not fit in with the surrounding architecture are where the bomb-proof doors are hidden. In the event of a nuclear attack, station staff will remove the steel plate from the floor, revealing a tunnel through which the door can move. When the door closes, people sheltering inside will avoid the heat, pressure and radiation of the nuclear explosion.

Since 2007, with the support of the Chinese Rocket Force, the entire Beijing subway system has been renovated with two layers of emergency protection above the station ceiling and underground. The door installed underground weighs 7 tons. Each station has a three-hour backup oxygen supply system.

In 2012, Chinese media announced that Beijing's subway system could protect residents from typhoons, nuclear attacks, and even toxic gases.

However, experts say the effectiveness of this measure has not been proven. If Beijing were to be hit by a nuclear attack, survivors hiding in the subway station would die later because after three hours they would have to open the door to get oxygen and would certainly be exposed to radiation.