Grotta dell'Elefante Bianco (Laghetto di Ponte Subiolo)

Down to -40 m you swim through a big passage with boulders, then over limestone slabs to the rim of the shaft at -52 m: the usual turn point. There is no silt or clay, so visibility holds during the dive, and normally there is no noticeable current in the main passage. In dry periods (especially in winter) the water is clear. In flood it discharges tens of m³/s, and after heavy rain the water stays murky for a long time (15 days or more according to a 1999 description).

The lake is named after a white rock on its floor that looks like an elephant; locally the cave is also called 'il pozzo della morte' ('the well of death'). The name Subiolo, the legend says, comes from flute-like sounds ('subio' in the local dialect) of the fairies who dance on the lake at night. The water comes from rain on the Asiago plateau.

It is one of Italy's most visited springs, also by foreign teams. Its depth was explored step by step: Jean-Jacques Bolanz reached -122 m, Olivier Isler -139 m and Luigi Casati -189 m in 2004 (Underwater 3D gives -186 m), about 530 m from the entrance. In February 2024 Bartłomiej Pitala's Polish CCR team pushed to -227 m with scooters, on a dive of ~6.5 hours. In 2026 Pitala, alone with a scooter, reached -292 m: from -235 m he followed a passage of over 100 m to the north to a fifth shaft, and below -280 m he saw a floor of large boulders. That dive took about eight hours, and it is the Italian cave-diving depth record.

Practical: a sign by the bridge sets out the rules, in Italian and English, and memorial plaques for the divers who died here hang on the far side of the lake.