Two kilometres east of the centre, on the slope of the original early-medieval settlement of Agadir, the partly ruined Great Mosque of Agadir preserves a minaret thought to be one of the earliest standing in the Maghreb. The prayer hall is roofless and largely collapsed, but the courtyard and the base of the mihrab can be made out, and the minaret itself still towers above the surrounding houses.
It is easy to miss — there is no big sign and the surrounding streets are residential — but worth seeking out as a piece of the city's earliest Islamic history. Combine with the walk up to Sidi Bou Medien, which is on the same hillside.