Off the coast of North West Africa, close to southern Morocco and West Sahara lies a group of islands called the Canary Islands. One of its most western islands is called La Palma (the islands belong to the kingdom of Spain). La Palma is basically just a volcano. It has erupted many times (last time in 1971), and, although controversial, there are predictions of it being close to erupting again soon, with devastating results: it is thought to be very likely to dislodge a 12 mile-long slab of rock that will crash to the ocean floor, causing a dome of water a mile high, causing a tsunami, travelling at 500 mph...
Atlantis?
“But afterwards there occurred violent earthquakes and floods; and in a single day and night of misfortune all your warlike men in a body sank into the earth, and the island of Atlantis in like manner disappeared in the depths of the sea. For which reason the sea in those parts is impassable and impenetrable, because there is a shoal of mud in the way; and this was caused by the subsidence of the island.”