Volcanic underwater bottoms. True seamounts can be seen in the image, a natural monument made of basaltic columns called a columnar disjunction. The highest point is about 15 meters below the surface of the Atlantic Ocean and drops vertically to more than 40 meters at its deepest point. The place is known as La Rapadura on the coast of Santa Úrsula, north of the island of Tenerife. Seabed of the Canary Islands.