Rabat's must-see sight – along with the neighbouring mausoleum – this iconic tower looms 44m above the Bou Regreg estuary. 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 it was completed. The mosque was destroyed by an earthquake in 1755, and today only this tower and a photogenic forest of shattered stone pillars remains in testament to his grand plan.