Eighteen kilometres of tunnels carved by lava 27,000 years ago, beneath the hills of Icod de los Vinos. The Cueva del Viento is the 5th longest volcanic tube in the world, and one of the best preserved. The guided tour (2h, 10 people maximum) descends into a network of galleries where the temperature remains constant at 19°C, where fossils of endemic giant lizards are embedded in the rock, and where lava formations take impossible shapes.
The tip: Book as soon as the calendar opens, three months in advance; time slots disappear within days. Closed shoes mandatory (slippery terrain). Light jacket recommended despite the constant 19°C.
When lava flows quickly from a volcano, the external surface cools and hardens within hours, forming a crust. Beneath this crust, the lava continues to flow, then eventually empties. What remains is a tunnel: this is the volcanic tube. In the case of Cueva del Viento, the eruption that formed it lasted several centuries, feeding a river of lava from the Teide to the sea.
The result: galleries that can reach 15 metres in height and 20 metres in width, with walls covered in formations called lavacicles (lava stalactites), shelves, and lava balls. Some resemble abstract sculptures, others giant intestines; the shapes are disconcerting.
The complete isolation of the cave allowed the evolution of species unique in the world. Fossils of Gallotia goliath, a giant endemic lizard from Tenerife now extinct, were found in Cueva del Viento, the best preserved in the Canaries. Spiders and insects adapted to total darkness still live in the deepest galleries.
The Interpretation Centre on the surface explains this underground biodiversity with models and specimens, worth seeing before the descent to better appreciate what you will observe.