The Cais do Marégrafo is located in Foz, close to the mouth of the River Douro. The low building was originally a customs post but has now been repurposed as a coastguard station along with the former telegraph tower.
You can just about make out the bare granite of the Sao Miguel-o-Anjo Lighthouse behind the tower. Built in the 1520s this is a very primitive lighthouse - although strangely there is very little sign of where the actual light would have gone.
