Description: The Great Pyramid of Giza (also called the Pyramid of Khufu and the Pyramid of Cheops) is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt, and is the only one of the Seven Wonders of the Ancient World that survives substantially intact. It is believed the pyramid was built as a tomb for fourth dynasty Egyptian Pharaoh Khufu (Cheops in Greek) and constructed over a 20 year period concluding around 2551 BC. The Great Pyramid was the tallest man-made structure in the world for over 3,800 years. Originally the Great Pyramid was covered by casing stones that formed a smooth outer surface, but what is seen today is mainly only the underlying core structure, with a few of the original casing stones that once covered the structure simply representing the four compass points around the base. There have been varying scientific and alternative theories regarding the Great Pyramid's construction techniques. Most accepted construction theories are based on the idea that it was built by moving huge stones from a quarry and dragging and lifting them into place.