The Titlis glacier grotto consists of an approximately 150-metre-long, artificially created passageway that leads around 20 metres below the surface of the glacier. The walls are covered with millions of glittering, ancient ice crystals, some of which are up to 5,000 years old. Two people explore the fascinating, blue-lit glacier grotto on the Titlis in Engelberg, Obwalden, Switzerland. They walk through the icy tunnel, which offers a unique experience in the Alpine landscape of Europe