Abisso Bonetti

Abisso Bonetti ("Bonetti Abyss") is a Karst cave in the municipality of Doberdò del Lago (Gorizia, Friuli-Venezia Giulia, Italy), 1 km (0.62 mi) SE from the small village of Bonetti, near Slovenian border (village of Nova vas). The cave is one of the most famous cavities in the Gorizia Karst. Anyway, due to its dangerous pit opening, entry is allowed only to expert cavers with the necessary equipment for single-rope descend.

Abisso Bonetti is one of the biggest and most well-known cavities in the Gorizia Karst. It opens 186 m (610 ft) above sea level, on a small plateau north of Jamiano (Doberdò del Lago), near Slovenian border. Overall, it is 87.5 m (287 ft) long and 49 m (161 ft) deep. Peculiarity of the cavity is its impressive opening, a 48 m (157 ft) deep, 30 m (98 ft) for 10 m (33 ft) wide abyss, that's an open pit in direct connection with the external environment. The cave has another entrance, that's a partially artificial gallery connected with the pit. During World War I, Austro-Hungarian Army built a shelter in the gallery. The bottom part of the open pit contains a rubble slope where detritus, plant materials and animal carrions, fallen down from the external environment, are collected. The innermost part of the cave is made up of an underground gallery after that, passing through a tight passage, a big hall is reached. The hall contains collapsed bedrocks and cave formations, including a column that seems like holding up the weight of the ceiling. Abisso Bonetti shows a climatic peculiarity. The innermost part of the cave has a stable temperature (12 °C (54 °F), that's the annual mean temperature in the place where the cave opens), a typical feature of cavities. In the bottom part of the open pit, the temperature varies between 10 °C (50 °F) in summer and 2 °C (36 °F) in winter. This part of the cave can be considered a cold trap.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).