The Pyramid of Cheops, also known as the Great Pyramid of Giza or Pyramid of Khufu, is the oldest and largest of the three main pyramids in the Giza necropolis. It is the oldest of the Seven Wonders of the Ancient World and is the only one still standing. Egyptologists believe that the pyramid is the tomb of the pharaoh Cheops (4th dynasty) and that it was built around 2560 BC. According to some it was built by the royal architect Hemiunu, with an original height of 146.6 m, reduced to the current 138.8 due to atmospheric phenomena.