Towering above the Bou Regreg estuary and surrounded by well-tended gardens, this 44m tower is Rabat’s most prominent landmark. It was originally part of an ambitious Almohad project to build the world's second-largest mosque (after Samarra in Iraq), but its patron Sultan Yacoub al-Mansour died before the building was complete. The mosque was destroyed by an earthquake in 1755, and today only this tower and a forest of shattered pillars testifies to the grandiosity of al-Mansour’s plans.