How were the Egyptian pyramids built?

The Great Pyramid of Giza, built for Pharaoh Khufu around 2560 BCE, contains an estimated 2.3 million blocks averaging over 2 tonnes each. Workers quarried limestone near the site and floated granite from Aswan, about 800 kilometres away, along the Nile. Blocks were dragged on wooden sledges, and a tomb painting shows workers pouring water on sand in front of a sledge, which experiments show greatly reduces friction. Archaeologists believe ramps, possibly straight, zigzagging or spiralling, raised blocks as the pyramid grew. Discoveries of workers’ villages and tombs show the builders were organised crews, not slaves, as was once believed.