Fort of São João das Maias - Credit: Wikimedia Commons
The Fort of São João das Maias, also known as the Fort of Oeiras, is located on the right bank of the River Tagus estuary, in the municipality of Oeiras in the Lisbon District of Portugal. It was constructed between 1644 and 1653. Until 2010 it had been allowed to fall into a state of advanced degradation but in that year it was restored. Read more on Wikipedia
Source: en.wikipedia.org