Portugal, Cascais, Boca da Inferno: Not named Inferno's Mouth for nothing, this ruptured cave inside the cliff face receives the unabated fury of the waves that role, or thunder in directly from the Atlantic Ocean. Whatever the weather, tide, current or wave condition the spectacle never fails to impress. Each wave smashes onto the rocks with a different formation, mesmerising in the same way as a roaring fire in a hearth.