Grotta della Bigonda (''The Bigonda cave (or Vigondola'' ) is a natural cave located in Valsugana, near Selva in

Grigno Grigno (''Grigno'' in local dialect) is a ''comune'' (municipality) in Trentino in the northern Italian region Trentino-Alto Adige/Südtirol, located about east of Trento. Grigno borders the following municipalities: Castello Tesino, Cinte Tesino ...

, in the province of

Trento Trento ( or ; Ladin and lmo, Trent; german: Trient ; cim, Tria; , ), also anglicized as Trent, is a city on the Adige River in Trentino-Alto Adige/Südtirol in Italy. It is the capital of the autonomous province of Trento. In the 16th centu ...

, on the right bank of the Brenta river. The cave can be visited, but only accompanied by a guide (this can be addressed to the Grotte di Selva Group), only during the

winter Winter is the coldest season of the year in polar and temperate climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Different cultures ...

season (since it is less rainy) and only for its first kilometer (more than necessary special equipment is required).

History

The entrance to the cave was discovered on March 28, 1952, during some marine research led by Eraldo Marighetti, which included the emptying of the pond for works in the aqueduct. The first 2.9 kilometers were detected by the company Tridentine Alpinists (SAT) of

, coordinated by Antonio Galvagni and Gino Tomasi. Subsequently, the Grove Grassland Group of Grigno continued the exploration, achieving more than 30 km of development. Access to the cave is located in the town of Ospedaletto, 458m asl, reachable from the village of Selva di Grigno in 30 minutes.

Description

The cave is predominantly located on three levels (combined with different diacylases and wells), with a north–south orientation, thus reaching the territory of the plateau of the Seven Communes; is the third Italian cavity for its vastness. The cave, also excavated in

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

, is rich in

stalactite A stalactite (, ; from the Greek 'stalaktos' ('dripping') via ''stalassein'' ('to drip') is a mineral formation that hangs from the ceiling of caves, hot springs, or man-made structures such as bridges and mines. Any material that is soluble an ...

stalagmite A stalagmite (, ; from the Greek , from , "dropping, trickling") is a type of rock formation that rises from the floor of a cave due to the accumulation of material deposited on the floor from ceiling drippings. Stalagmites are typically ...

s and hypogeous fauna (18 different species of animals, including some absolutely unique in world taxonomy) and currently it has been measured a maximum difference between -108 and +350 meters, or about 450 meters. The interior of the cave varies according to the season, or rather rainfall, during the slightly rainy seasons

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

s and

siphons A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in a ...

are formed, making this cave a cave rich in water (at a temperature of 3 °C). Twenty-five ponds, with high boots, or a canoe and 21 siphon lakes, have been counted, which can only be exceeded by using special diving equipment. In the heavily rainy seasons, however, the cave is lurking completely and is no longer accessible.

References

{{Reflist Caves of Italy