20.7083°N, 30.3250°E.
Long Nile island in northern Sudan, roughly 12 kilometres in length and occupied more or less continuously from the Palaeolithic period through the Ottoman period. Sai Island contains an exceptional stratified archaeological sequence: Kerma-period elite cemeteries from the third and second millennia BCE, a fortified New Kingdom Egyptian colonial town founded by Ahmose I around 1530 BCE complete with a stone temple of Amun, a Napatan and Meroitic occupation, a Christian Nubian settlement with multiple churches, and an Ottoman fortress built in the late sixteenth century to control the river crossing. The site was excavated by Jean Vercoutter for France beginning in 1954 and is currently directed by Florence Doyen and Vincent Francigny under the French archaeological mission to Sudan. Pharaonic administrative buildings include the rare survival of a New Kingdom palatial residence with intact painted floors and column bases still in position.
Few sites anywhere on Earth preserve six successive civilizations as visibly stacked as Sai does on a single island in the middle of the river.