The easily recognisable Santa Marta lighthouse stands on what was once the southern tip of Cascais (the marina now extends beyond the point). Built in 1868 on the site of a 17th century fort the lighthouse only came into operation after the site was stripped of its military status.
Santa Marta's distinctive blue and white striped tower stands at 8 metres (25ft) tall and still stands guard over the mouth of the Tagus. Until 1981 it was manned continuously by lighthouse keepers, however these days the light is automated.
The lighthouse and fort now incorporate a small museum which covers the site's history as well as the development of the optical devices used in Portugal's lighthouses. There are interactive collections of lights and optics along with multimedia presentations. Another topic covered by the museum is the lighthouse keeper's profession.
On the terrace of the fort, overlooking the Cascais cliffs, is a pleasant little cafe.