São Pedro do Estoril Fort is a military fortress of defense of the coast built in the 17th century XVII, in a Mannerist architecture style, in a strategically spot for the defense of Lisboa region and the entrance of the Tagus river.
From the exterior defensive structures on the inland side, there is nothing left.
Nowadays the Fort belongs to the Portuguese State but is rented ,and in its interior there is the “Forte Velho” night club.