Explanation:

The Great Pyramid, commissioned and built by the Pharaoh Khufu, is one of the oldest buildings in existence. It is 456 ft. high and thought to be nearly 4500 years old. Archaeologists believe Egypt's large pyramids are the work of the Old Kingdom society that rose to prominence in the Nile Valley after 3000 B.C. Historical analysis tells us that the Egyptians built the Giza Pyramids in a span of 85 years between 2589 and 2504 BC. Tourists are allowed to enter all three of the great pyramids, for a fee, of course. That is, you can go into the Great Pyramid of Khufu, the Pyramid of Khafre and the Pyramid of Menkaure as long as you pay for a ticket.