These are not actually The Cliffs of Insanity, as everyone knows they are in Ireland. Or, really, they are in a book and a film, that portion of which was filmed over at Moher.
Instead, these are the sea cliffs at St. John’s Head, on the island of Hoy, Orkney. These are some of the highest cliffs in the UK, standing at a sheer 352 metres (1154 feet). When you take the ferry to Orkney and back, assuming you travel from Scrabster to Stromness, then you will pass beneath these cliffs (unless the seas are too rough, then you try and sneak through Scapa Flow, to the east of the island of Hoy, instead or, as often happens, you have to wait for calmer seas).
The entire western coastline of Orkney is constantly being ground and battered into smaller and smaller fragments of rock; breakers that have had the entire Atlantic ocean to grow smash into these cliffs, cracking and splintering. It is a powerful thing, to stand atop as the thump of the waves can be felt through the ground. Walking along cliffs, feeling the power of nature, is a favourite of mine.