Aigües Tower, Barcelona

This is the only courtyard left in the Eixample district that's still open to the public. When the famous architect Cerdà designed the neighborhood he wanted the courtyards to be play areas for children and common areas. All that's left of this courtyard is the Torre de les Aigües (Water Tower), which has been converted into a kind of artificial beach where people can swim. While you're here, wander the quaint alleyway (Passatge Permanyer) located opposite the tower.