This fortress is located by the seashore road and is partially hidden by some woods. It is called "Forte Velho" (Old Fortress) due to the fact that it is the oldest in the region. It was built by Dom Filipe I and enlarged by Dom João IV in 1643.
Summer house where stands out, abroad, a porch on the first floor, with monochrome panels clipped profile from the 18th century. Inside, still stands out in the foyer, the 19th century polychrome tile factory of Santana and, in the dining room, ashlars multi-colored plastic neoclassical treatment.
This palac was built at the beginning of the 20th century by the capitalist Jorge O'Neill according to the plan of the architect and painter Manuel Vilaça. Like a medieval castle it has several styles, namely the romantic style with gothic references, manuelin and Spanish-Arabic. In 1910 the count bought the building and made several changes to it. By testament, this building was left to the people of Cascais and a small museum and a library were introduced. It as several interesting works, many of which regarding Cascais, and some Indian-Portuguese furniture, namely counters of the 17th and 18th centuries.
Built during the reign of Dom João IV, this fortress still maintains its primitive structure with its scuttles, its patrol walk and its stairways. The barrack, located in the middle of the stronghold and of the two waters rooftop, is very well preserved.
A fortress built during the reign of Dom João IV, although the exact date of its primitive construction is unknown. There are still several vestiges of that construction, namely a gate with an inscription and the royal arms.
When the Portuguese maritime expansion had its peak, in the 16th century, Cascais was one of the first places to have a lighthouse. The Guia lighthouse was built in 1610 and a small hermitage was built in the surrounding area with the following inscription: "Guide of the seamen".