Information from Wikipedia
https://en.wikipedia.org/wiki/Colossi_of_Memnon
The statues are made from blocks of quartzite sandstone which was quarried at el-Gabal el-Ahmar (near modern-day Cairo) and transported 675 km (420 mi) overland to Thebes (Luxor). The stones are believed to be too heavy to have been transported upstream on the Nile. The blocks used by later Roman engineers to reconstruct the northern colossus may have come from Edfu (north of Aswan). Including the stone platforms on which they stand – themselves about 4 m (13 ft) – the colossi reach 18 m (60 ft) in height and weigh an estimated 720 tons each. The two figures are about 15 m (50 ft) apart.
The original function of the Colossi was to stand guard at the entrance to Amenhotep’s memorial temple (or mortuary temple): a massive construct built during the pharaoh’s lifetime, where he was worshipped as a god-on-earth both before and after his departure from this world. In its day, this temple complex was the largest and most opulent in Ancient Egypt. Covering a total of 35 hectares, even later rivals such as Ramesses II’s Ramesseum or Ramesses III’s Medinet Habu were unable to match it in area; even the Temple of Karnak, as it stood in Amenhotep’s time, was smaller.
