Túnel de la Atlántida (English: Tunnel of Atlantis) is located in the Canary Islands off the coast of North Africa. A lava tube, or pyroduct, is a natural conduit formed by flowing lava from a volcanic vent that moves beneath the hardened surface of a lava flow. If lava in the tube empties, it will leave a cave.

A lava tube is a type of lava cave formed when a low-viscosity lava flow develops a continuous and hard crust, which thickens and forms a roof above the still-flowing lava stream. Tubes form in one of two ways: either by the crusting over of lava channels or from pāhoehoe flows where the lava is moving under the surface.

Lava usually leaves the point of eruption in channels. These channels tend to stay very hot as their surroundings cool. This means they slowly develop walls around them as the surrounding lava cools and/or as the channel melts its way deeper. These channels can get deep enough to crust over, forming an insulating tube that keeps the lava molten and serves as a conduit for the flowing lava. These types of lava tubes tend to be closer to the lava eruption point.

Tunnel de la Atlantida is the underwater portion of the Cueva de Los Verdes lava tube at Haría, Las Palmas. The 1,500-meter-long tube formed some 20,000 years ago when the Monte Corona volcano erupted on the island of Lanzarote. The erupted molten rock flowed across the land and into the ocean.

At present, the Atlantis Tunnel is immersed in the Sublantida project, the first geological study carried out in the cave. The aim of Sublantida, launched by the UNED, is to reconstruct the evolution of the sea level over the last 20,000 years.

According to Wikipedia/ fascinatingspain