Boca do Inferno

Useful Information

Boca do Inferno, Portugal. Public Domain.
Location: At the coastal road in Cascais.
(38.6914, -9.4306)
Open: no restrictions.
Fee: free.
Classification: Speleologysea cave. Geologynatural bridge
Light: n/a
Guided tours:
Photography: allowed
Accessibility: wheelchair accessible
Address: Boca do Inferno, Av. Rei Humberto II de Itália 642, 2750-642 Cascais
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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1896 film A Sea Cave Near Lisbon shot to show the waves.
1929 Guilherme de Faria commits suicide.
1930 Aleister Crowley fakes his death in the cave.


The Boca do Inferno (Mouth of Hell) is a collapsed sea cave which is quite famous. The cave has been a tourist destination for centuries, mostly because It's conveniently close to Lisbon. The waves crashing into the cave are quite dramatic at times, so one of the first films ever was shot in this caves in 1896. Its name was simply A Sea Cave Near Lisbon.

The famous magician, occultist and astrologer Aleister Crowley chose this place to fake his suicide. He wrote a suicide note which read "Não Posso Viver Sem Ti. A outra ‘Boca De Infierno’ apanhar-me-á não será tão quente como a tua". The mangled Portuguese with many Thelemic symbols roughly translates "Can’t live without you. The other mouth of hell that will catch me won’t be as hot as yours.". The poet Fernando Pessoa helped him by handing Crowley's suicide note to newspapers. He even assisted with translating the note to police and media alike. Three weeks later an exhibition of Crowley's works was opened in a Berlin gallery, and Crowley reappeared magically. It is not clear if this was simply a publicity stunt or intended to annoy Crowley's lover. The event is commemorated by a small white plaque at the outlook, which tells the story and provides the text of the suicide note.

However, there was an actual suicide one year earlier. The poet Guilherme de Faria who published his first volume of poems at the age of 14 committed suicide at the age of 21. Quite strange is the fact that he looked like Fernando Pessoa. But probably he was the inspiration for Crowley's hoax.

The sea cave is located conveniently at the coastal road, with a huge parking lot, a seafood restaurant and an outlook. A huge part of the cave has collapsed and there is only a natural bridge remaining. The cave is oriented northwest to southeast, obviously a fault zone or a layer of weak rock, which was easily washed out by the water. But the waves from the Atlantic ocean hit fom the west or southwest, an so there is the former entrance to the sea cave, The ceiling of the cave collapsed along the weak zone and so the natural bridge and a huges sinkhole remain. From the first outlook you can see the sinkhole and through the sinkhole and natural bridge to the sea. There is a second outlook at the edge of the cliff which allows a few to the natural bridge from the sea side.