The quarry for the Colossi has been identified at Gebel el Ahmar near modern Cairo, and Egyptologists believe the blocks were moved during the annual Nile flood using a combination of sledges and water lubrication on wetted tracks.
What makes the logistics genuinely staggering is that the statues were commissioned by Amenhotep III around 1350 BCE, a pharaoh who also built more monuments than almost any other ruler in Egyptian history, yet left almost no records explaining how any of it was actually done.