Situated by the sea and around 10 kilometres from Lisbon, the town of Oeiras has for centuries been the place chosen by many noble or wealthy families for their summer residences. The most important of these buildings are the 18th century palace of the Marquis of Pombal, King Dom José's minister who contributed greatly to the development of Oeiras and its elevation to the category of a town, and the Real Quinta in Caxias.
In the 17th century a series of fortifications was built along the coast to defend the mouth of the Tagus, and therefore the entrance to Lisbon. The most notable are the Forte do Areeiro, the Forte das Maias, the Forte de Catalazete, the Forte de São Bruno in Paço de Arcos and, the most typical, situated in the middle of the Tagus - the Forte do Bugio.
In the environs, it is worth visiting the Museu da Pólvora Negra (Gunpowder Museum) in the premises of the Antiga Fábrica da Pólvora (Old Gunpowder Factory) in Barcarena, which has been deactivated and turned into a leisure area, the Museu do Automóvel Antigo (Veteran Car Museum) in Paço de Arcos, and the Vasco da Gama Aquarium in Dafundo.
On Sundays the bric-à-brac markets enliven the council's gardens, taking place on the first Sunday of the month in Santo Amaro de Oeiras, then in Paço de Arcos and, on the last Sunday, in Algés.