Patriarcal Reservoir

The Patriarchs' tank is one of the cisterns that in the past supplied the inhabitants of Lisbon with drinking water. It is located underground below Principe Real Square. It is currently a branch of the Water Museum.

The tank was built in 1864 according to the design of the French engineer Louis-Charles Mary. It was part of the modernization of the city's infrastructure and the construction of water supply installations to all districts. Water was supplied by means of aqueducts.

The tank is an underground structure based on a system of arches and over thirty pillars. It has the shape of an octagon. Wooden platforms were run between them, so you can see the whole room. There is still water on the bottom of the tank.