The Ahrntal is Italy's northernmost valley and ends at Predoi (Prettau), a village of just under 600 inhabitants. Copper was mined here from the 15th century onwards, for around 500 years. Today the mine is a museum — and home to the Climate Tunnel, where guests are treated to a form of speleotherapy tolerated even by children.

The reason for the effect lies in the tunnel's climate. At about 95 percent humidity and a constant eight degrees Celsius, particulate matter and allergens bind to the damp rock walls. What remains is air without dust, pollen and pollutants. This "speleotherapy" has been in use since the 1990s in the disused St. Ignaz Tunnel and is recognised as an accompanying treatment for asthma, bronchitis and allergies. Guests ride the mine train around one kilometre into the mountain and stay for two hours, lying or sitting on loungers.

All around lies the Rieserferner-Ahrn Nature Park with peaks over 3,000 metres. Several businesses in the valley have joined together in the Respiration association and offer allergy-friendly rooms, certified by the South Tyrolean Environmental Agency. The Ahrntal is thus one of the few Alpine destinations that combines pure mountain air, therapeutic infrastructure and quiet at the end of a dead-end valley — no through-traffic, no mass tourism.