Fodor's Expert Review Aqueduto das Águas Livres

Stretching for more than 18 km (11 miles) from the water source on the outskirts of the city, the Aqueduct of Free Waters began providing Lisbon with clean drinking water in 1748. The most imposing section is the 35 arches---the largest of these is said to be the highest ogival (pointed) arch in the world---that stride across the Alcântara River Valley north of the Amoreiras Shopping Complex in the neighborhod of Campolide. Nearer the city center, another 14 arches run 200 feet along the Praça das Amoreiras, ending in the Mãe d'Agua, an internal reservoir capable of holding more than a million gallons of water. This extraordinary structure is open for visits, providing a chance to see the holding tank, lavish internal waterfall, and associated machinery.