Boca do Inferno (which translates to "Mouth of Hell" in English) is a dramatic and famous cliff formation located in Cascais, Portugal. This natural landmark is known for its striking beauty and powerful waves that crash against the rocky cliffs, creating a mesmerizing yet somewhat ominous scene. The name "Boca do Inferno" comes from the loud, thunderous noise the waves make as they enter the caves and crevices, often resembling the sound of a roaring beast.