The tunnel formed by La Corona Volcano is one of the longest and most interesting on the planet. All along it, there are at least sixteen "Jameos" (a jameo is a volcanic cave with a collapsed roof). Over six kilometres of the tunnel have been explored, and they extend from the crater of the volcano before entering the sea in an underwater stretch of one-and-a-half kilometres, known as the "Túnel de la Atlántida" (Tunnel of Atlantis).