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Geosite 5 · Sinkholes and abysses of the Cansiglio

> Pozzo dei Bellunesi <

The “twin” of the Bus de la Lum: discovered in 1981 by cavers from Belluno, it reaches −175 m and joins the Lum’s final chamber.

Cadastre no. 35061894 FRMunicipality of Caneva
1040m a.s.l. · entrance
−175m · depth
210m · total length
Sìalong the Ring of the Abysses

Part of the Bus de la Lum – Bellunesi complex: 186 m total height difference, down to the bottom of the Bus de la Lum at 854 m a.s.l.

From the guide

Audio guide (Italian) · Bus de la Lum – Pozzo dei Bellunesi
0:00 / 1:45

The Bus de la Lum opens at an altitude of 1,030 metres a.s.l. in the Friulian part of the basin, forming a wide, elliptical funnel among the tall trees of the forest. The name “Lum” (“light”) derives from ancient legends that told of flames spotted near the chasm, attributed to fantastic creatures or, more realistically, to will-o’-the-wisps produced by the decomposing carcasses of animals that had fallen into it. It is a vertical cavity 186 metres deep, formed by the union of two abysses, with a planimetric length of 718 metres. One is the main one, now fenced off, which was explored by the Trieste-based C.G.E.B. Trieste in 1924, while the other was discovered by a Belluno-based team in 1981 near the original abyss and was subsequently named the “Pozzo dei Bellunesi”. Initial interest in the Lum began in 1901 when the engineer Luigi Marson launched a sounding line into the chasm, recording a depth of 460 meters. This incorrect estimate made the abyss the deepest in the world, obviously arousing curiosity and interest. This measurement was later reduced to 195 m. At the bottom of the cave, a perennial waterfall is fed by icy waters originating from a narrow gorge-like passage known as the “Ramo dello Scoiattolo”. The stream sinks into the debris deposits and is eventually absorbed within the “Salone della Lanterna”. The Bus de la Lum is a cavity which is historically and sadly notable for events related to the Second World War, when, in the final months of the conflict, soldiers and civilians were thrown into it. At least 28 bodies were recovered in the 1960s and were buried in the Caneva cemetery.

What it looks like

  • Entrance with a 31 m shaft, followed by drops of 35, 9, 13 and 94 m.
  • Vertical sections alternate with a small chamber, a canyon, low passages and a two-level gallery.
  • The bottom is the same two-fracture chamber as the Bus de la Lum.

Water and air

It shares the Squirrel Branch stream and waterfall with the Bus de la Lum.

Did you know? Two 40–50 m chimneys in the hall have been climbed without finding continuations: exploration is still open.

History of the explorations

  1. 1981

    Discovery and first survey by Gruppo Solve CAI Belluno

  2. 1992-93

    Digging by Gruppo Solve

  3. 2004

    Survey of the Squirrel Branch

  4. 2012

    Plaque placed by the Gruppo Speleologico Sacile

  5. 2021

    Survey update (F. Felici)