Hidden Doors in The Great Wall of China

The Great Wall of China is a remarkable structure, stretching over 13,000 miles. Its construction began over two millennia ago and has been updated and modernized by different emperors over the years. Surprisingly, researchers have discovered over 220 secret doors along the wall - some allowing only one person to pass through and others accommodating horses.These doors were strategically placed to maintain the wall's defensive integrity.A research group has looked through official historical documents of the Ming Dynasty that ruled China from the 14th to the 17th centuries. They came across records of secret doors in the Great Wall, so they decided to find them. They used a flying robot to capture continuous centimeter resolution photos of the wall. They photographed 90 percent of the wall that was built during the Ming Dynasty and discovered the remains of over 220 secret doors along the wall. Some of them have a specific width and height that allows only one person to go through; others are large enough to allow two horses to pass at the same time.

Why are the doors there? Well, the Great Wall’s main goal was to protect the country from the enemy. Building doors that could let the enemy in would undermine the whole point of having a wall. So, of course, the doors were secret passages. They perfectly matched the surroundings topographically, and the exit on the outside was camouflaged with bricks so that it was almost completely indistinguishable from the brick wall. The wall was never just a defensive wall, and it was never completely closed; it could be opened on demand. It was also a structure used for trade and commerce, communication between inside and outside the wall, and, of course, for defense and spying.

Some doors were used for trade with the other side. Through smaller doors, a person would sneak out to spy on the enemy that lived on the other side. The hidden gates were also useful for a sudden attack. As you remember, some gates were camouflaged with brick on the outside; the exit was so indistinguishable that the enemy had no idea exactly where it was located. The inside entrance for Chinese soldiers was hollow, so they could walk through the wall and break the camouflage exit gate from the inside, starting their surprise attack.

The first parts of the wall were built out of rammed earth and wood; these are not the most unfailing materials if we’re talking about thousands of years. Also, destructive farming methods have turned large areas into a desert and contributed to erosion. Also, many bricks were taken away from the wall in the last century to be used in building farms and houses. The wall is being deconstructed stone by stone even today, but this time by tourists. Quite a few of them take a stone as a souvenir. That’s a total of a lot of stones. Even though the main point was to prevent outsiders from getting into the city, the wall wasn’t too effective on that matter; it could still be climbed over or marched around. So the wall was being watched at all times, and the guards gave signals to the troops if they saw the enemy approach. Also, the wall provided more time to mobilize and bulk up the country’s forces or lure the enemy troops into a difficult strategic position.

Despite its historical significance, the Great Wall has faced challenges over the centuries, including erosion, human damage, and the removal of bricks for other construction projects. Today, only eight percent of it remains in good condition. Recognized as a UNESCO World Heritage Site since 1987, the Great Wall of China is not just a tourist attraction but also hosts the Great Wall Marathon, one of the world's most challenging marathons. Italy leads the world in UNESCO World Heritage Sites with 58 while China boasts 56 thanks to this iconic structure.