This point sits at the Santa Marta Lighthouse, a working lighthouse and lighthouse museum on the old fort grounds south of Cascais.
Last reviewed 4 October 2026 · A three-minute read · 2870 BC–2007
The short answer
Santa Marta Lighthouse, on the old fort grounds south of Cascais, has guided ships since its red beam first lit on 1 March 1868. Built over a 17th-century fort raised after the 1640s to guard the Tagus bar, it was converted to a lighthouse in 1864 and now operates alongside a museum that opened in July 2007.
Cascais, Portugal — 2007 · Pedro Ribeiro Simões from Lisboa, Portugal · CC BY 2.0
1640s to 1864
A fort guarding the Tagus became unneeded for war
The Santa Marta Lighthouse is a working lighthouse and museum, built on the grounds of a 17th-century fort. The fort probably went up sometime after 1640, part of a coastal defense plan ordered by the Count of Cantanhede to guard the mouth of the Tagus River. A 1663 plan by the architect Mateus do Couto shows it already holding a battery and a barracks around a central courtyard.
The fort grew over the following century. Between 1762 and 1763, the garrison widened its parapet. In 1793, the engineer Romão José do Rego enlarged the battery further and pushed new quarters into the courtyard space. By 1864, the navy judged the fort no longer worth defending on military grounds. Its position was still useful for something else: guiding ships past the rocks at the edge of Cascais Bay.
1866 to 1908
A red beam first crossed the bay in 1868
The architect Francisco Pereira da Silva designed a lighthouse for the old fort, and the Lighthouse Service took charge of the site on 8 November 1867. Its red light first burned on 1 March 1868, built from a small tower added that same year. The light worked two jobs at once: marking the harbor and lining up with the Guia Lighthouse to guide ships through the bay.
A report from 1897 described a square white tower with a blue band, its lamp fed by a lens and a mirrored reflector. In 1908, a stronger fifth-order lens replaced the old apparatus, the same type of lens the lighthouse still uses today.
The tower grew again in 1936, raised eight meters higher after new buildings nearby blocked its light from ships leaving the river's northern channel. Electricity reached the lamp in 1953. Keepers kept watch here for decades more, until full automation between 1980 and 1981 removed the need for a resident crew. The light keeps working today, now folded into a museum that opened in July 2007 and still shares the ground with an active aid to navigation.
20th century to 2007
A cannonball surfaced as the fort became a museum
The fort and lighthouse grew shabby across the 1900s, worn down by salt air and decades of use. By the start of the new century, the Cascais Municipality and the Portuguese Navy agreed to fix it. Architects Francisco Aires Mateus and Manuel Aires Mateus led the restoration between 2003 and 2007, working alongside Joaquim Boiça. Workers restored the lighthouse's blue-and-white tile cladding in 2006. Diggers on the site turned up a cannonball during the project. Every other object in the museum today came from the Navy's own Lighthouse Directorate, but that cannonball stayed untouched, the one piece nobody restored.
The restored fort reopened as a museum in July 2007. Its setup was new for Portugal: a working lighthouse and a public exhibition sharing the same walls, still supervised by the Navy's Lighthouse Directorate.
2007 to now
A keeper's diary now sits where keepers once worked
Inside, two exhibitions tell the site's two lives. The other follows Santa Marta itself, from fort to lighthouse, and the people who kept its light burning. A lighthouse keeper's diary sits on display, filled with notes on foggy nights and clear ones, a record of a job that no longer exists here.
The tower today stands about 20 meters tall, striped blue and white, capped with a red lantern. Its fifth-order Fresnel lens still throws a white-and-red light 18 nautical miles out to sea, the same type of lens installed back in 1908.
2025 to 2026
The museum closed, then reopened hosting art and puppetry
The museum closed briefly on August 1, 2025, while crews finished renovation work and cleared equipment from the site. Rua do Farol, the street leading to it, closed along with it.
By 2026, the museum was running again, hosting LandArt Cascais and puppet shows among its exhibition rooms, with events scheduled into December.
The lighthouse still signals ships off Cascais Bay, its lamp turning above a museum built into the walls of a 17th-century fort.
Read the ground you are standing on
Every person, building and event in this story opens into its own dig in the app — and Strata will dig the ground under your feet instead, wherever that is, in about a minute, with every source shown.
A short walk along the shore, the Casa de Santa Maria was designated a Monument of Public Interest, marking it as one of the seafront's architectural landmarks.
On March 1, 1868, architect Francisco Pereira da Silva's new lighthouse lit its red beam for the first time, crossing with the Guia Lighthouse to guide ships into Cascais Bay.
After years of decline, the restored fort reopened in July 2007 as a museum, the only place in Portugal combining a working lighthouse with an exhibition on its own history.
Archaeological work ahead of the museum's opening turned up a cannonball, the one object in the display not supplied by the navy's own lighthouse collection.
A 17th-century fort stood on the site, built after the 1640s on the orders of the Count of Cantanhede to guard the mouth of the Tagus River, with a battery and barracks around a central courtyard.
When did the Santa Marta Lighthouse first light up?
Its red beam first burned on 1 March 1868, designed by architect Francisco Pereira da Silva and built to cross with the Guia Lighthouse to guide ships into Cascais Bay.
Is the Santa Marta Lighthouse still a working lighthouse?
Yes, its fifth-order Fresnel lens, installed in 1908, still throws a white-and-red light 18 nautical miles out to sea, even as the site also operates as a museum.
When did the lighthouse become automated?
The lighthouse was fully automated between 1980 and 1981, ending the need for a keeper to live on site.
What happened during the museum's restoration?
Between 2003 and 2007, architects Francisco Aires Mateus and Manuel Aires Mateus led a restoration with Joaquim Boiça, restoring the blue-and-white tile cladding in 2006; archaeological work during the project turned up a cannonball, the one object in the museum not supplied by the Navy's Lighthouse Directorate.
When did the museum close and reopen most recently?
The museum closed on 1 August 2025 for renovation work, along with Rua do Farol, and by 2026 was running again, hosting events such as LandArt Cascais and puppet shows.
