A Cova das Choias

A Cova das Choias is a karst cave in the municipality of A Pobra do Brollón, in the province of Lugo, on the edge of the Ribeira Sacra area bordering the Sierra do Courel. It sits in the parish of Óutara, close to the hamlet of Biduedo, and stands out as one of the most unusual natural sites in this part of Galicia, combining raw geology with centuries of mining history.

How do you get there?

The approach runs through Biduedo: drive the paved road to where it ends, then continue on foot along a dirt track toward the cave entrance. The terrain is mountainous, so sturdy footwear and extra time are worth planning for. Independent exploration of the interior isn't allowed — access is managed by the local town council (concello), which runs seasonal guided visits to protect the site.

What will you see inside?

The cave unfolds across three levels, with passages and chambers totaling over 100 metres, roughly 20 metres wide, and a vault that tops 30 metres in height in places. The middle level is generally considered the most rewarding, showing off rock shapes carved by water alongside clear traces of past human digging. Several galleries are dead ends, adding to the sense of a natural labyrinth.

The cave's standout feature is Schistostega pennata, better known as goblin gold moss — in low light its cells reflect a faint golden-green glow, a rare optical trick found in only a handful of places worldwide. The cave also shelters bat colonies, another reason behind the strict limits on casual entry.

Where does the name come from, and what's the history?

The name comes from "choias," the Galician word for red-billed choughs — crow relatives with a curved, bright-red beak that have long nested near the cave mouth.

While the cave itself formed naturally through water and wind erosion of limestone, much of its interior was shaped by mining. Iron ore was extracted here first during Roman times, between the 1st and 3rd centuries AD, and then far more intensively in the 16th and 17th centuries, when the ore fed forges and ironworks across the Lemos region. That mix of natural formation and industrial archaeology is what makes Cova das Choias distinctive, beyond its scenery alone.

When should you visit, and how does it work?

Because the ecosystem inside is fragile — the glowing moss and the bat colonies in particular — access has been restricted for several years. Visits are only possible through the seasonal guided-tour programme run by the A Pobra do Brollón town council, typically scheduled during the summer months. Exact dates shift from year to year, so it's worth checking the current schedule directly with the council or on its website and booking ahead, since each tour takes a limited number of visitors.

Frequently asked questions

Can you visit the cave on your own? No. For several years now, entry has only been possible on a guided tour organised by the local council, mainly during summer.

Why is the cave called "Choias"? It's named after red-billed choughs, crow relatives with curved red beaks that traditionally nested at the cave's entrance.

What's the main highlight inside? The glow-in-the-dark moss Schistostega pennata, along with remnants of iron mining dating back to Roman times and continuing into the early modern period.

How do you reach the cave? Through the hamlet of Biduedo — follow the paved road to its end, then continue on foot toward the entrance.