Aqueduto das Águas Livres
Stretching for more than 18 km (11 miles), this aqueduct began providing Lisbon with clean drinking water in 1748. An imposing section of 35 arches—including one said to be the world's highest ogival (pointed) arch—stride across the Alcântara River Valley. Nearer the city center, another 14 arches run 200 feet along the Praça das Amoreiras, ending in the Mãe d'Agua reservoir ( Praça das Amoreiras 8), where you can explore equipment. Art lovers are in for a treat, too: Immersivus Gallery ( 91/065–8479, portugalagenda.com) shows feature works by artists like Klimt, Kahlo, or Van Gogh projected onto walls and water, transforming them into a giant canvas.
