An aqueduct is a system that collects and transports water using gravity. When the Aqueduto das Águas Livres (Free Waters Aqueduct) was opened in 1748, it supplied drinking water to Lisbon.
Stretching for almost 60km (37mi), the chosen trajectory was that of the old Roman aqueduct. Águas Livres Aqueduct survived the earthquake of 1755, and only stopped supplying water to the city in the 1960s.

Aqueduto das Águas Livres
Today, you can walk across a section of the aqueduct of about 1km over 35 arches, though you may need a good head for heights.
How to Get to Lisbon’s Aqueduct
The walkable section of the aqueduct is a bit outside the city centre, and not easy to find. The entrance is off a quiet residential street through a small park in Campolide.
By bus
Take bus 702 from Praça Marquês do Pombal, direction Serafina, using your Viva Viagem card. Get off at stop Calçada dos Mestres (if in doubt, ask the driver for the aqueduct). Walk about 120m to the aqueduct entrance and ticket office.
By taxi
For ease, take a taxi or Uber.
Calçada da Quintinha 6, open Tuesday to Sunday from 10am to 5.30pm, www.epal.pt