Giza's most famous landform and archaeological site, the Giza Plateau, holds some major monuments of Egyptian history, and is home to the Great Sphinx. Once thriving with the Nile that flowed right into the Giza Plateau, the pyramids of Giza were built overlooking the ancient Egyptian capital city of Memphis, across the river from modern day Cairo. The Giza Plateau is also home to Egyptian monuments such as the tomb of Pharaoh Djet of the First Dynasty, as well as that of Pharaoh Ninetjer of the Second Dynasty. The Great Pyramid of Giza at one time was advocated (1884) as the location for the Prime Meridian, a reference point used for determining a base longitude.