The Great Pyramid
Two and a half million blocks, aligned to true north within a twentieth of a degree.
- When
- Known to
- ± 50 years
- Era
- Bronze Age, Holocene
Khufu's pyramid at Giza, finished around 2560 BCE, stood 146 metres tall and remained the tallest structure on Earth for nearly four thousand years. Its sides are aligned to the cardinal directions with an error of a few arcminutes and its base is level to within a couple of centimetres. It was built by a rotating corvée of paid labourers housed nearby, not by slaves — a fact established by excavating their bakeries, barracks and cemeteries.