Boca do Inferno is a sea chasm on the coast west of the town of Cascais, formed where the roof of a cave cut by the Atlantic collapsed and left an open cavity with a natural arch. The name means Mouth of Hell and refers to the force of the waves inside the chasm in stormy weather.
The site is on the coast road between Cascais and Guincho, next to the Atlantic cliffs.
What to see at Boca do Inferno
- Chasm and arch: the waves enter the collapsed cave and break against its walls. Viewing platforms look down into the cavity and through the arch towards the sea.
- Cliffs: the limestone cliffs on either side of the chasm, worn by the sea.
- Crowley plaque: a plaque recalls September 1930, when the English occultist Aleister Crowley staged his own disappearance here with the help of the Portuguese poet Fernando Pessoa, and appeared in Berlin some weeks later.
Visiting Boca do Inferno
- Access: the site is next to the coast road, with open access and paved paths to the viewpoints.
- Best conditions: the waves show the most force in winter storms and at high tide.
- Safety: the cliff edges are unprotected in places, so visitors keep to the paths and platforms.
- Nearby: the coast road to Guincho continues west and north from Boca do Inferno.
Places to visit in Cascais
Cascais, Portugal
Estoril, Lisbon
History of Cascais
Visiting Cascais
Boca do Inferno
Citadel of Cascais
Casa das Histórias Paula Rego
Condes de Castro Guimarães Museum
Santa Marta Lighthouse Museum
Cascais & Guincho
Marina de Cascais