"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 quarter. 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." (Wikipedia) We couldn't go inside today since it was a men only day, but families are allowed on Thursday.

For the "adventure" that goes along with this series, see this image of a totally contrasting kind of architecture: