Inside of Free Waters Aqueduct

The Águas Livres (Free Waters) Aqueduct was built from 1731 to 1799 by the King’s order. It is a vast system for collecting and transporting water using gravity. It has had National Monument status since 1910 and is considered to be a remarkable work of hydraulics engineering.
This work implied using the water springs of the Águas Livres, integrated in the Sintra mountain range catchment basin, in the Belas region northwest of Lisbon.
In general, the chosen trajectory coincided with that of the old Roman aqueduct. It was only possible to build it through the levy of a tax called the “Water Royal” duty on essential goods such as olive oil, wine and meat.
The system, which withheld the 1755 earthquake, is composed of:
A main section, 14 km long, which starts at Mãe de Água Velha in Belas and ends at the Mãe de Água das Amoreiras reservoir in Lisbon
Several secondary sections to transport water from around 60 sources
Five galleries for supplying around 30 fountains in the capital city
In total, the Águas Livres Aqueduct system, inside and outside of Lisbon, was about 58 km long in the mid-19th century. Its waters were no longer used for human consumption as of the 1960’s.
The extraordinary arches of the Alcântara valley, which cover a length of 941 metres, correspond to 35 arches in all, including the largest stone arch of this type in the world at 65.29 m high and 28.86 m wide.

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