Shannon Cave 

The raison d'être of the Shannon Group, it was the attempt to re-enter this long-inaccessible system in 2005 that brought the founders of the Shannon Group together. Since then this cave has been the group's primary project, with near-constant digging, exploring, diving, and surveying in the years since. The most recent phase of explorations has brought the length of the system up to 8.6km, and has established it as arguably Ireland's premier cave system.