Hölloch: inside one of Europe's largest cave systems

Beneath the meadows of the Muotatal lies the Hölloch. With more than 210 kilometres of explored passages it is the longest cave in Switzerland and one of the longest in Europe and the world. Between its lowest and its highest point lie 1033 metres. No other cave on earth combines such depth with such length. Unlike many record-breaking caves, the Hölloch is open to visitors: the guided tours range from a comfortable two-hour round to a multi-day expedition with a night in the cave bivouac.

A short history of a very long cave

The farmers of the area had always known the hole in the rock near Stalden. Scientific exploration began in 1875 under Alois Ulrich. By 1906 the first 700 metres had been developed as a show cave with paths and stairs. The great leap came in the 1950s with the caving pioneer Alfred Bögli. His expeditions extended the surveyed length from 25 to more than 100 kilometres. The Hölloch was thus the first cave in the world to pass that mark. Surveying continues to this day: a connection discovered in 2020 confirmed the combination of depth and length that is unique worldwide. How far the system really reaches, nobody knows. Water dissolved this labyrinth on three levels out of the limestone in barely a million years, and it is still at work.

The tours: from a walk to an expedition

Every visit is guided, because the cave is a genuine labyrinth. The starting point is the Hölloch centre in Stalden, Muotathal. Inside the mountain it is a constant 6 °C in summer as in winter, with humidity close to 100 %. The main options at a glance:

• Short tour (about 2 h, from age 5). It leads through the developed historical section with stairs, paths and impressive chambers. The guides usually have an atmospheric surprise in store, for instance a moment when you hear the natural acoustics of the cave. A sure step is enough.
• Beginners' tour (about 3 h, from age 6). This adds detours into undeveloped side passages, giving you a first impression of what real caving feels like.
• Hölloch parcours (about 3.5 h, from age 9). The classic for the adventurous follows an underground route with climbing sections, ladders and crawling passages. With average fitness it is well within reach.
• Day expeditions (7–11 h, roughly November to mid-March, from age 10). These lead deep into the system and have the character of a mountain tour. Expeditions run only in winter, because meltwater and rain make parts of the cave dangerous in summer. Underground the seasons are thus exactly the other way round.
• Multi-day expeditions. The night is spent in the «Dom» bivouac deep inside the mountain. Anyone who would like to spend a night inside a mountain can book it here as a guided trip.

You need to reserve for all tours, because group size is limited. Those who are afraid of narrow spaces usually worry more than they need to. Even the tightest sections of the tours can be passed comfortably. In the darkness you also barely notice how deep inside the mountain you are.

Kit

Helmet and headlamp are provided on site. Bring sturdy, waterproof shoes with a good sole and warm clothing to layer, because it really is only 6 degrees. For the parcours and the expeditions, clothes that are allowed to get dirty are advisable. On the tours with climbing sections, gloves are a good idea.

Getting there

• Public transport: by train to Schwyz, then by bus 501 towards Muotathal to the stop «Hölloch, Muotathal». The same bus also serves the Stoos funicular, so a visit to the Hölloch combines well with the Stoos. More on the Stoos: Stoos Ridge Hike.
• Car: there are signposted paying car parks at the Hölloch centre (satnav: «Stalden 14, 6436 Muotathal»). Opposite the restaurant there is a charging point for electric cars.
• For a meal after the tour, the Restaurant Hölloch right by the entrance is the obvious choice.

Combining the visit with the Muotatal

Around the cave you can easily spend a whole day in the Muotatal, a valley that has kept much of its own character. The weather prophets, the husky treks, the Bödmeren primeval forest and the Suvorov trail all lie nearby. More about the valley in the article The Muotatal.

Frequently asked questions

How long is the Hölloch? More than 210 kilometres have been explored. That makes the Hölloch the longest cave in Switzerland and one of the longest in the world. This length combined with 1033 metres of vertical range exists nowhere else on earth.

Can you visit the Hölloch without a guide? No, every visit is guided. The cave is an active labyrinth in which researchers have been shut in for days by rising water. Only the guiding and the permanently installed safety systems make a visit safe.

Is the Hölloch suitable for children? Yes. The short tour is possible from age five, the beginners' tour from six, the parcours from nine and the day expedition from ten.

How cold is it in the cave? All year round it is a constant 6 degrees with very high humidity. Dress warmly, whatever the weather outside.

Why do the big expeditions only run in winter? In summer, meltwater and rain can flood the deeper passages within hours. In winter the surface is frozen and holds the water back. That is why the deep cave stays dry and safe at that time.

Do you need caving experience? For the short tour, the beginners' tour and the parcours you need none. Day and multi-day expeditions call for good stamina, but no technical background.