Gruta das Torres

In the vineyard country of Criação Velha, on the western slopes of Pico Island, a stone stairway drops through a collapsed skylight into the dark: the Gruta das Torres, the longest lava tube known in Portugal, runs more than five kilometres beneath the vineyards of Madalena.

A river of fire underground

The cave is the fossil bed of a lava river: as the flow poured down from the volcanoes above, its surface cooled into a hard shell while the molten centre kept running, hollowing out a tunnel. The result is a corridor of black stone several metres high, lined with ledges, stalactites of re-melted lava and the marks of the flow that made it.

Into the dark

Visits are guided and cover a few hundred metres of the tube, with helmet and lamp provided from the visitor centre above ground — a genuine wild cave rather than a lit show cave. Outside, the same lava fields carry the walled vineyards of the Pico vineyard culture, listed by UNESCO as World Heritage in 2004, and the cone of Mount Pico stands over it all.

What to see

• The entrance shaft and stone stairs
• The lava ledges and stalactites of the tunnel
• The guided route through the first hundreds of metres
• The visitor centre at the surface
• The walled vineyards of Criação Velha above the cave

Practical information

The cave entrance lies near Criação Velha, in the Madalena municipality of Pico, a short drive from the port town. Inside the temperature is cool and constant — bring a layer and sturdy shoes. Visits follow a guided schedule that changes with the season; check official information and book ahead in summer.

Image credit: Gruta das Torres by José Luís Ávila Silveira/Pedro Noronha e Costa — Public domain, via Wikimedia Commons.