Crater — Arabic Kraytar — is the oldest part of Aden, occupying the floor of the extinct volcanic caldera that gives it its name. The volcanic walls rise on three sides, the harbour fills the fourth. Almost every sight in central Aden is here: the Cisterns of Tawila, the Aidrus Mosque, the National Museum, the British-era market streets, and the grid of late-19th-century commercial buildings.
The district is dense and walkable, but parts are run-down and conflict damage has touched many buildings since 2015. The market — the souq behind the museum — is the best place to see the city at work.