The pyramids were the tombs of the kings of ancient Egypt. These rulers were called "pharaohs" in history. The ancient Egyptians'' religious belief in God made them form a deep-rooted "concept of afterlife" very early. They even believed that "life is just a temporary stay, and after death, it is a permanent enjoyment". Therefore, the Egyptians regarded the underworld as a continuation of their earthly life. Influenced by this "concept of afterlife", ancient Egyptians prepared for death with sincerity and confidence when they were alive. Every rich Egyptian was busy preparing his own tomb and decorating it with various objects in order to achieve immortality after death. In terms of pharaoh or nobles, he would spend several years, even decades, to build tombs, and ordered the craftsmen to continue to engage in sailing, hunting, feasting activities with tomb murals and wooden models, as well as the work that servants should do, so that he could live comfortably after death as before.