Boca do Inferno is a scenic cliff formation located near the town of Cascais, Portugal, about 30 kilometers west of Lisbon.
The name "Boca do Inferno" means "Hell's Mouth" in Portuguese and is derived from the rough, turbulent waters that crash against the rocks, creating a roaring sound that is reminiscent of the fires of Hell.
The cliffs at Boca do Inferno were formed over millions of years by the pounding of waves against the rocky coastline. The cliffs rise up to 20 meters high and are made up of layers of sedimentary rock, with visible fossils embedded in the rock face.
Today, Boca do Inferno is a popular tourist destination, with a path leading down to a viewing platform that offers spectacular views of the cliffs and the Atlantic Ocean. There are also several small caves and grottoes in the area that can be explored at low tide.