They were constructed of many thousands of years ago. The pharaohs of Ancient Egypt wanted their bodies to be protected and not go bad. Each pyramid had the body in a pyramid with all their belongings and goods to their next life.
The same pharaoh who is responsible for constructing the Sphinx built the Pyramid of Khafre. That pharaoh’s name is Khafre he is the son of Khufu and one of the Ancient Egyptian kings who ruled for 26 years. The pyramid of Khafre is one of the largest pyramids in Ancient Egypt, the height of the Pyramid of Khafre is 488 ft tall.
The Pyramid of Khafre is about the same height as the Great Pyramid of Giza