In this event dedicated to the Water Cycle in Lisbon, we propose a route that starts in Jardim das Amoreiras, next to the entrance to the Mãe d'Água Reservoir. From there we'll set off, following, whenever possible, the section of the Águas Livres Aqueduct, which we'll visit, as well as the Monsanto Forest Park, towards Amadora, where this stage will end, next to the Falagueira Adventure Park. At the end of the stage, you can return using the blue metro line from Amadora or Reboleira station.

Note: This event includes a visit to the Águas Livres Aqueduct.

Águas Livres Aqueduct:

Built between 1731 and 1799 by royal order, the Águas Livres Aqueduct was a vast system for collecting and transporting water by gravity. Classified as a National Monument since 1910, it is considered a remarkable work of hydraulic engineering.

This work involved using the Águas Livres water springs, which are part of the Sintra mountain basin, in the Belas area, north-west of Lisbon.

The route chosen coincided, in general terms, with the route of the old Roman aqueduct. Its construction was only possible thanks to a tax called the Royal Water Tax, levied on essential goods such as olive oil, wine and meat.

The system, which withstood the 1755 earthquake, consists of:

• A main section, 14 kilometres long, starting at Mãe de Água Velha, in Belas, and ending at the Mãe de Água das Amoreiras reservoir, in Lisbon
• Several secondary sections designed to transport water from around 60 springs
• Five galleries to supply around 30 fountains in the capital

In total, the Águas Livres Aqueduct system, inside and outside Lisbon, was around 58 kilometres long in the mid-19th century, and its waters were no longer used for human consumption from the 1960s onwards.

The extraordinary arcade of the Alcântara Valley, which stretches for 941 metres, is made up of 35 arches, including the largest stone ogival arch in the world, 65.29 metres high and 28.86 metres wide.