Engineered in the 18th century, the Águas Livres Aqueduct runs over and through Lisbon, offering some of the best views of the city. A well-preserved series of 109 stone arches, it was built in 1744 to bring clean drinking water to the city’s residents. The historic structure still stands tall, having survived the massive earthquake of 1755 without damage. Its main arches span 11 miles (18 kilometers), with the entire aqueduct covering nearly 36 miles (58 kilometers) in length. At its tallest point, the arches tower 213 feet (65 meters) high; it was the largest arch in the world at the time it was built.
A walk along the top grants viewpoints of both sides on the river of the city below. Though high up, the passage ways are wide and the Museu da Água (Water Museum) at its base explains the history of the complex water systems and structures here.
The aqueduct is open Monday to Saturday between March 1 and November 30. It is closed during the winter season and on Sundays and public holidays. It is located on Praça das Amoreiras, and the closest metro stop is Rato for the museum or Campolide train station for views of the aqueduct.