Construction of the Great Pyramid

Some 2.3 million limestone blocks were quarried, floated, dragged and set within roughly two decades. The workforce was not enslaved but organised: rotating gangs with names like 'Friends of Khufu', fed on bread, beer and Nile fish.

Precision is the astonishing part. The base is level to within a few centimetres and aligned to true north within a fraction of a degree.