Beginning cavers and spelunkers are severely discouraged from entering and negotiating the cave. Many other caves can be accessed with a permit by experienced cavers. During the 1935 expedition another group of cavers explored Lower Cradle Hole Cave. The area around the mountain has over 200 caves that attract visiting cavers. However, vertical cavers have often encountered longer stalactites while exploring. In 1999 a team of cavers and industrial archaeologists announced plans to investigate the tunnel. In 1961 the cave was rediscovered by cavers, who found human bones. Kiernan and a group of cavers (speleologists) found over 100 caves in the region. Communication between cavers and people on the surface may be essential for rescues or expeditions. They are still employed by cavers, hunters, and cataphiles. The mountain contains a large number of lava tubes, which are frequented by cavers. A Purcell Prusik is a related cord popular among cavers and rope-rescue people. From Five Arches, several routes are open to cavers. Such long trips necessitate the cavers carrying provisions, sleeping and cooking equipment. The Federation represents the Bulgarian cavers and speleologists.