Unknown structure of the Chephren pyramid

The Cheops and Chephren pyramid have been in Giza for about 3500 years. Their view is enjoyed by many people around the world who ask questions: how and why were the pyramids built? Cheops and Chephren pyramids are very similar on the outside. According to what we know, however, they are diametrically different in their internal structure. In the Chephren pyramid the internal structure was not discovered while the Cheops pyramid has many internal chambers, like: The King's Chamber, the Queen's Chamber. However, according to current knowledge, the Mummies of Pharaoh and his wife were never buried there. So, why were the internal structures of this pyramid built? Were the pyramids supposed to be a visible sign of Pharaoh's power? Are there any undiscovered chambers in both pyramids, which could give us answers to many questions