The Masmak (Arabic: Qaṣr al-Maṣmak قصر المصمك‎‎) is a clay and mud-brick fort, with four watchtowers and thick walls, founded on stone blocks, lying in the center of Riyadh, in the old quarters. This building played a major part in the kingdom's history, as it was here that the recapture of Riyadh, led by Ibn Saud, occurred on 14 January 1902.