The Great Wall of China is the longest wall in the world. The total length of all the sections added together is more than 21,000 kilometers. Researchers have recently found that parts of the wall have been preserved over time by something called a biocrust. This is a thin layer of plant life.
The Great Wall of China was built in sections over a period of more than 2,000 years. The first parts were started around 220 BC. Its purpose was to prevent invaders from coming into China from the north. The most famous parts of the wall were built from stone, but in some areas, it was built using “rammed earth”. Over time, wind and rain can easily wear down rammed earth, so scientists have often questioned how these old sections of the Great Wall have managed to survive for such a long time.
A group of researchers from China Agricultural University in Beijing examined a 592-kilometer long section of the wall and found that more than two thirds of it was covered in biocrust. The scientists took some samples of the biocrust back to their lab for testing and found that the natural material was actually stronger than the rammed earth. Some pieces of the plant-based layer were up to three times stronger. This means that the biocrust has actually strengthened the wall and protected it from being worn down by weather over the years.
These findings could be important for people who manage ancient structures all over the world. Although biocrust may not look attractive, its natural ability to preserve things makes it a very useful tool for experts looking for ways to protect valuable ancient buildings.
