Kazumura Cave

By 1993, a single year of extensive surveying established that it was the longest in the world. Originally, Kazumura was two separate caves known as Upper Kazumura and Old Kazumura. Kevin Allred and Mike Meyer connected the two caves after seeing a small connection and enlarging it to permit entry. More connections were made later at Paradise Park Cave when it was connected to Kazumura through a breakdown pile. Later, a culvert was installed to keep the passage stable. Sexton Cave was discovered nearby; its passage ended where Kazumura's began. After some digging in black lava rock, Kevin and Mike Shambaugh got close to connecting these two caves. Eventually, Shambaugh connected them after continuous digging. Kevin and Carlene Allred then surveyed the combined caves to a total of , which made it the longest lava tube in the world.