Answer:
The Egyptian Pyramids were first built for their pharaohs. In their religion, it is to be believed that in order to succeed in the afterlife, the corpse needs to be kept deep inside a temple buried in with gold and treasure.
The pyramid had many halls and rooms to also keep other family member, servents, or anyone close/related to them. They also has false rooms in order to trick future robbers from stealing the treasure.
I believe that the pyramids were kept as Ancient World Heritage sites for a variety of reasons. One reason is the size. Pyramid of Giza is a very tall structure, ranked as the tallest man-made structure in the world for 400 years. Not only that, but pyramids are important artifacts of the past, displaying the culture of those before us.
