Casa de Santa Maria was built in 1902 for Jorge O'Neill — an Irish-Portuguese aristocrat — and remained in private hands until 2004, when the municipality acquired it. It is one of the finest surviving aristocratic villas of the Cascais Riviera era, and a model example of the eclectic late-nineteenth-century Portuguese revivalist style.
The interiors are entirely panelled in azulejos, some of which were rescued from older Lisbon palaces during the early twentieth-century building booms. The garden steps down toward the rocks, and several of the rooms have direct sea views. The house is open as a museum and hosts occasional temporary exhibitions.