Fort of Alto do Duque

The Fort of Alto do Duque is located 75 meters above sea level at the southwestern tip of the Monsanto Forest Park, in the parish of Ajuda, in Portugal's capital of Lisbon. Built at the end of the 19th century as part of Lisbon's Campo Entrincheirado (Entrenched Field) defensive ring around the city, with the intention that it, together with the Fort of Bom Sucesso, would defend against attacks along the River Tagus, the fort is now headquarters of the criminal investigation division of the Polícia de Segurança Pública (PSP) in Lisbon.