The thick darkness of Grotta Su Marmuri – experience the power of nature first-hand.

Do you think Sardinia is just about azure coastlines, the scorching sun and the scent of sun-warmed maquis? We thought so too, until our route took us to the area around Ulassai. Just a few dozen minutes’ drive from the sun-scorched valleys, the mountains harbour a secret that literally makes your blood run cold – and that’s no metaphor at all. We’d already explored various places on this island, but descending into Grotta Su Marmuri was like crossing the threshold into another dimension.

It starts off quite innocently. An open, rusty gate set in an old stone arch invites you onto the trail. The sun is still beating down, and you walk on in your light, summery clothes, suspecting nothing. But suddenly the air grows thicker. With every step towards the entrance, you’re struck by an unnatural, deep chill, as if the mountain were breathing cold air straight from the bowels of the earth.

Swallowed by darkness When you stand at the edge of the entrance, the sheer scale of the place is simply overwhelming. This is no cramped hole in the ground that you crawl into on all fours. It is a gigantic, gaping cave mouth, reached by a long flight of steps. With every step down, the greenery and the harsh light of day are left behind, and you plunge into the twilight. Look at this photo of people descending – the silhouettes look like tiny ants being swallowed up by the abyss. This sight evokes that distinct thrill of excitement when you know that in a moment you’ll discover something truly monumental.

8.5 degrees and the power of silence The information boards at the entrance weren’t lying. Laser measurements and sensor readings show clearly: regardless of whether it’s the height of a sweltering summer outside, inside Grotta Su Marmuri there’s a constant, austere temperature of around 8.5°C. Contrasted with the Sardinian heat, stepping into this cool mass of air comes as a shock.

When we reached the very bottom and set off along the marked path, an overwhelming silence descended. Walking along the floor of this immense canyon, several dozen metres deep and carved out of the rock, one subconsciously lowers one’s voice to a whisper. The high, vertical walls disappear somewhere into the darkness above. It is just you, the chill and the echo of your own footsteps reverberating off the damp stone.

An art gallery sculpted by water The further in you go, the darker and more fascinating it becomes. Formations that defy gravity and human logic began to emerge from the darkness. Hundreds of thousands of years of slow, methodical dripping water have created an underground art gallery here.

On our way, we came across rock draperies – thin, pleated stalactites that look exactly like heavy, theatrical curtains frozen in stillness. A little further on, a gigantic, massive column emerged from the darkness. Soaring, with intricate carvings resembling melted wax, it connects the floor to the vaulted ceiling like a pillar supporting the entire weight of the mountain. You look at it and realise that this masterpiece was formed drop by drop, back when prehistoric beasts still roamed the earth.

This place is captivating in its mystery. You follow the marked trail and, with every step, you long to see what lies beyond the next bend in the rock. A walk through Grotta Su Marmuri is a journey through a place where time flows at its own pace, imperceptible to us.

When at last, after a long walk in the darkness, we returned to the starting point and felt the hot Sardinian sun beating down on our faces once more, it took us a while to shake off that dark dream. Su Marmuri leaves a lasting impression. It’s one of those moments on a trip when you realise just how little you know about the power of nature until you look it straight in the eye.