Boca do Inferno

Boca do Inferno is a rocky chasm on the Cascais coast where a sea cave once collapsed, leaving an open arch. Atlantic Ocean water flows through this opening at high speed, creating dramatic displays of spray and mist.

The site was first documented by British filmmakers in 1896 and appeared in an early documentary about the Portuguese coast. It has remained a known location where visitors can observe nature's power ever since.

The name comes from local folklore about the dangers of these cliffs and the sea's power. Visitors come to experience the raw force of the ocean and witness how water crashes against the rocks in ways that feel both chaotic and beautiful.

The location sits along a coastal path and can be reached on foot from Cascais, with several viewing platforms dotted along the route. Visitors should watch for slippery surfaces and stay careful during stormy conditions, as spray can reach far from the rocks.

During heavy winter storms, water fountains shoot from the opening so high that they tower above the surrounding cliffs. This phenomenon draws many visitors who want to witness the ocean's raw power at its most extreme.