Blanche Cave, previously known as "The Big Cave", "The Old Cave" and "Mosquito Plains Cave", is one of 26 caves to be found in the Naracoorte Caves National Park, a World Heritage listed site. Blanche Cave was the first of the caves to be discovered in the Naracoorte area, having been discovered by the European settlers in 1845, and can be accessed by the public through guided tours of the site.
The cave contains a number of features, including, at one time, the mummified remains of an indigenous man – remains that were stolen twice in 1861 and never returned. The location has been the site for a number of events, such as, in the early days, annual New Years parties and, much more recently, it was featured as part of the Olympic torch relay for the 2000 Summer Olympics in Sydney.
The cave consists of three chambers. The entrance chamber, located at the south-eastern end of the site, contains the old wooden tables and benches. The second, or middle, chamber has two "windows" – holes in the roof that permit light to enter the space – located at either end of the chamber, and which provide two of the three possible entrances to the cave. This area also contains a number of dry columns. The third chamber is also the largest, and is where the "Lost Exhibit" is located. It contains the remains of a bat guano quarry, (the "Devil's Pit"), and a structure known as the "Post Office".
The deterioration that had been noted in 1879 has been, to some extent, reversed. Even at the time, the correspondent noted that "the restorative action of nature is very rapid", and that the scars were being healed. However, the planting of pine trees prevented water from percolating through the cave, limiting its restoration and, indeed, causing further deterioration of the decorations. Fortunately, the removal of these trees in the late 1980s have permitted rejuvenation to continue.