The Great Pyramid of Giza is the largest Egyptian pyramid. It served as the tomb of pharaoh Khufu, who ruled during the 4th Dynasty of the Old Kingdom. Built c. 2600 BC, over a period of about 26 years, the pyramid is the oldest of the Seven Wonders of the Ancient World, and the only wonder that has remained largely intact. It is the most famous monument of the Giza pyramid complex, which is part of the UNESCO World Heritage Site "Memphis and its Necropolis". Initially standing at 146.6 metres, the Great Pyramid was the world's tallest human-made structure for more than 3,800 years. The base was measured to be about 230.3 metres square.