What kind of books are the Classic of Mountains and Seas in ancient China

The Classic of Mountains and Seas was a book on ancient Chinese mythology, legends, geography, biology, religion, and other aspects. It was a monumental work with rich content and was known as the encyclopedia of ancient Chinese mythology. It recorded myths and legends, monsters, gods, mountains and rivers, scenic spots and historical sites in different parts of ancient China. It had a profound impact on ancient Chinese culture, folk customs, beliefs and other aspects.