Ancient ruins submerged in the tropical rainforest - Angkor Wat.

In ancient times, there was a Chinese man named Zhou Daguan. In 1296, he sailed south to the Khmer Dynasty and stayed for 1 year. His official identity was an envoy of the Yuan Dynasty. It is not clear what his real mission was, and it is not clear why he wrote an interesting book "The Customs of Cambodia" after returning to China. This book was translated into French in 1819. By 1861, French botanist Henri Mouhot found the ancient ruins submerged in the tropical rainforest - Angkor Wat in the Mekong River Basin based on the clues in this book. Angkor Wat, along with the Great Wall of China, the Taj Mahal in India, and Borobudur in Indonesia, are known as the four wonders of the ancient East.