The Imam Mohammed bin Saud Mosque, just outside the At-Turaif walls, is a large modern mosque in the traditional Najdi style — pale earth-coloured walls, angular minaret, palm-shaded courtyards. It is named for the founder of the First Saudi State, who agreed the famous 1744 pact with the religious reformer Muhammad ibn Abd al-Wahhab here in Diriyah.
Non-Muslim visitors are normally not admitted to the prayer hall, but you can walk the exterior and the gardens. A useful counterpoint to the polished restoration of At-Turaif.