[citation needed] During World War II and the Post-War period, the area's royal affiliations intensified, as many heads of European royal houses and deposed monarchs, including King Edward VIII of the United Kingdom, King Juan Carlos I of Spain, and King Umberto II of Italy made their home in Cascais and Estoril, finding refuge in Portugal's neutrality in the war or from tense political situations in their own countries.

[12] Due to its concentration of high-profile personalities, the riviera became a center of espionage during WWII, inspiring author Ian Fleming in his creation of the James Bond series.

[13][14][15] Sintra had been a royal retreat since the Portuguese Renaissance in the 15th century, but it was in the 19th century, when King Fernando II of Portugal decided to build his summer retreat, Pena Palace, in the Sintra Mountains overlooking the Atlantic Ocean, that it became both the center of the Romanticist movement in Portugal and the summer residence of the Portuguese nobility.

In the summer of 1787, William Beckford stayed with the Marquis of Marialva, master of the horse for the kingdom, at his residence of Seteais Palace.

At the beginning of the 19th century Princess Carlota Joaquina, wife of the Regent John, bought the estate and Ramalhão Palace.

The landscape, covered in fog, also attracted another Englishman, Francis Cook, who occupied the estate, constructing an oriental pavilion.

The Portuguese Riviera originated when King Luís I of Portugal ordered a royal residence to be constructed in Cascais Citadel, starting the tradition of Cascais being the Portuguese royal family's Summer residence, which lasted from 1870 to 1908, transforming the seaside village into a cosmopolitan address.

Cascais also benefited from the construction of better roads to Lisbon and Sintra, a casino, a bullfight ring, a sports club, and improvements to basic infrastructure for the population.

[26] During that time, several dignitaries and exiles came to Estoril: Miklós Horthy, the regent of the Kingdom of Hungary (lived and died in exile after the Second World War); the Infante Juan, Count of Barcelona (father of Juan Carlos I of Spain) and the King resided in the territory, as did Umberto II of Italy and Carol II of Romania.

The region has a Mediterranean climate, influenced by the Atlantic Ocean and characterized by moderate temperatures and wet winters.

The coast along Praia do Guincho, located within the bounds of the Sintra-Cascais Natural Park, is known for its particularly strong winds and powerful waves, making it a popular destination for surfing, kitesurfing and windsurfing.

The Portuguese School of Equestrian Art, one of the "Big Four" most prestigious classical riding academies in the world, is based at Queluz National Palace in Sintra.