The Vigant-Pre Oreak complex is the result of the union of an about 30 m siphon of two separate caves: the Vigant Abyss (Fr 66) that serves as absorbing cavity and the Pre Oreak cave (Fr 65) or Pre Oreach that is the old system of water outflow system. To these two entries, another entrance of recent discovery must be added which intercepts the Vigant Abyss at its initial gallery. The total development of the complex is of 1870 m with a drop of 280 m. The entrance to the Pre Oreak Cave is at 293 metres under the sea level and starts with a slightly down-hill gallery with an abundant clay deposit. After walking a path of about thirty metres towards South, the path slightly goes up until reaching the large dome-shaped hall (30 metres long, 20 metres wide and 20 metres high) characterized by the presence, on the South side, of a large calcitic flow and majestic cluttered rocks. Once passed the hall, a walkable path leads to an ample, slightly down-hilled gallery that turns North after about fifty metres and arrives to a water pool that is kept at a constant level by an absorbent cleft; on the left, there are two little indententions with some fractures each one corresponding to water outflows that infiltrate into the sandy and slimy deposits of the cave floor. Walking onwards, there is the second large hall characterized by a large deposit of cluttered rocks that are covered by a massive, about ten metres thick slimy-argillaneous clutter. Passed the hall, on the right, the gallery turns into a circular shape and continues for some metres downhill until it reaches the siphon that is characterized by a clear water pool that leads into a 30-metres-long flooded passage that reaches the bottom of the Vigant Abyss. The entrance to the Vigant Abyss is from a rocky wall; the entrance to the cavity is very ample (about 10 x 7 m) and is clearly visible. Through a majestic ten-metres high portal, there is the access to the first length of the slightly down-hilled cavity that ends with a little 4 metres-high leap under which there is a large bowl-shaped erosion pothole with a water pool; recently an elevated stone path was created which allows also the tourists to visit this part of the cavity. This first length is partially illuminated because of the entrance vastness; by walking it, as well as firstly crossing the torrent, someone must pay particularly attention as the floor is always very slippery: this is the reason why it is always necessary to follow the rigged path. A series of pits (one of which is 80 m deep), often alternated to little ponds, leads to the final gallery that leads to the about 30 m-long siphon that connects the Vigant Abyss to the Pre-Oreak cave. In the article are also described the fossil faunas found in particular in the Vigant Abyss and are examined the few notes related to traditions and legends that interest this karst system.