Of all the seven wonders of the ancient world, only the pyramids of Giza still stand today. Pharaoh Khufu commissioned the building of the first and largest pyramid, while his son Khafre and grandson Menkaure commissioned the other two.
Pharaohs used pyramids as burial chambers for their mummified bodies. Ancient Egyptians believed that when a pharaoh died, he transformed into the king of the dead and needed to be buried with his material possessions from this life.
Slaves did not build the pyramids as was once popularly believed. Archaeologist Mark Lehner thinks that ordinary Egyptians built the pyramids under labor obligations not unlike those which existed in feudal Europe in the Middle Ages.
In 2002, archaeologists used the Pyramid Rover, a small robot, to explore a shaft of the Khufu pyramid. The robot drilled a small hole through a limestone door and inserted a camera only to reveal that a second door blocked the view.