1746 to 1834: the long build
The final reservoir of the Águas Livres Aqueduct started in 1746, stalled, changed, resumed in 1771 under Reinaldo Manuel dos Santos, and was only completed in 1834. Carlos Mardel, who shaped the aqueduct's arrival at Rua das Amoreiras, died in 1763 before the work was finished. That drawn-out timeline explains why the reservoir feels less like a single neat gesture and more like a city project refined in stages.
Why the interior feels almost sacred
Inside, the reservoir does not read like industrial infrastructure first. The broad hall, the light, the still water, and the vaulted cover give it the mood of a chapel or cistern-palace. That surprise is part of the appeal: you come for engineering history and end up in one of Lisbon's strangest meditative rooms.
The Register House matters too
On the western front sits the Register House, where flows to fountains, factories, convents, and noble houses were once controlled. This detail is easy to miss, but it changes how you read the site. The reservoir was not just storage; it was part of a carefully managed urban distribution system.