The Pyramids and Sphinx http://www.pbs.org/wgbh/nova/pyramid/explore/howold.html NOVA Online/Pyramids/How Old Are the Pyramids? pbs.org The age of the great pyramids of Giza and the Sphinx has been debated over the years by Egyptologists and archaeologists. The history books indicated 3200 B.C. as the approximate date when the pyramid of Khufu was under construction. Egyptologists and archaeologists have thought the Great Sphinx of Giza to be about 4,500 years, but some say it goes back 9,000 years.