Aquaduct of the free waters.
I saw this aquaduct in a film by Wim Wenders, “Lisbon Story” and made sure I took a look at it while I was in Lisbon.
It’s a beautiful structure that spans across the Alcantara valley in the middle of the city, Construction began in 1732 and it started supplying water to the city in 1748, however it is no longer in use. There are 35 arches, 14 ogival as shown in this sketch. It is amazingly tall in the middle and very impressive, considered a masterpiece of baroque engineering. Auto and rail traffic now streams through the arches in the valley bottom.
I was able to go out and walk across the top as it is a museum now, the views out over the city are fantastic.
I’d say it’s well worth a visit if you are in Lisbon.
More info at this link: http://en.wikipedia.org/wiki/%C3%81guas_Livres_Aqueduct