Forte de São João Baptista da Foz
Aldoar, Foz do Douro e Nevogilde, Portugal
The Fort São João Baptista da Foz (Forte de São João Baptista da Foz in Portuguese), is located in the parish of Foz do Douro, in the municipality and District of Porto, in Portugal. It stands in a dominant position at the mouth of the Douro river, overseeing the access the city of Porto via the river.
Fort data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).