Fascinated by Aqueducts but never had a chance to get close to one.
My first visit was on a public holiday. It was closed. Came the following day prepared. Had a good wallow in it and out; up and down; front and back...well you get the picture.

The Aqueduto dos Aguas Livres was situated slightly out of town, to the north-west of Lisbon. It was built about 400 years ago with a total length of 58 km crosses the Alcântara Vally, over a distance of 941 metres with a series of arches that reach 65 metres at their highest point. There are a few options to visit depending on where you're staying. I find doing it yourself quite a thrill.

A good place to start I think is from this small shaded garden hidden behind a bunch of suburban buildings by the side of Tagus River at Rua de Amoreiras where an old man working in a home style ticket office in the garden. You pay 3.50euro he would then point you to a walkway at the end of the garden where it'll eventually lead you out and up the stairs to climb to the top of the Aqueduct. Up the top, a bird's eye view offering 360 degrees over the city of Lisbon. It feels surreal to be able to walk into the endless water tunnel on top and then crossed out to the other side facing another part of the city, and then, if you like, come back again in a few seconds. I felt I was in a trance for a moment or two. What makes it more interesting was that there was hardly anyone around. The aqueduct isn't a tourist hotspot. Locals knew it's there but they've never bother to get up there.
I liked it this way. A place to chill, to hide, to contemplate, to write some diaries with a cool drink-at the same time taking in the panoramic view.

Tips: If coming from centre Lisbon, take metro to Marquēs de Pombal come out across the square take bus 702, about 7 stops or ask any locals on bus. A taxi about 8 euro. There were a few small cafes and a small supermarket not far from the shaded garden.