Fort of Alqueidão
Santo Quintino, Portugal · built 1809
The Fort of Alqueidão, also known as Forte Grande (Big Fort), is located about 2 kilometres south of the parish of Sobral de Monte Agraço, in the municipality of Sobral de Monte Agraço, in the Lisbon District of Portugal. It was one of the first and one of the largest of 152 military works known as the Lines of Torres Vedras that were built in 1809-10 to defend Lisbon during the Peninsular War (1807–14). The fort played a major role in stopping the advance of Napoleonic troops.
Fort data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).