The fortress
Imam Abdullah bin Faisal bin Turki Al Saud began building al-Masmak in 1865. Its walls are of mud mixed with hay on stone foundations, plastered with clay outside and gypsum inside, and the outer wall is up to 2 m thick.
Four round watchtowers rise 18 m at its corners. Its entrance door, 3 m by 2 m, is made of tamarisk and palm wood. Inside are about 44 rooms on two floors, with courtyards, majlis rooms, a mosque and a well.
The museum
Restored in 1980, the fortress is now the Historical Al-Masmak Museum. Its halls display photographs, maps, display cases, old weapons and traditional heritage pieces.