The volcano of Mysterious Island, Mount Prometheus, has become Captain Nemo's base. After traveling through its caverns and past several of Nemo's labs (which includes a diary entry of the discovery of the fossilized egg of a monstrous, unknown arthropod), guests board "Terravators" (elevators) to the facility's base station one-half mile below. In this base station is a huge steam-powered bellows that pumps fresh air down from the surface, massive spring-pillars that hold the ceiling up to prevent cave-ins in case of earthquakes, and communication center which is currently giving warnings of increased seismic activity, but the scientist who mans it is currently away on a tea break.
Riders then board steam-powered mine vehicles that travel through pre-drilled tunnels into the heart of the Earth. The ride begins through a cavern of colorful glowing crystals, before entering a giant Mushroom Forest, which is inhabited by strange insect and amphibian-like life forms. Before the car can proceed further, an earthquake causes a cave-in of the tunnel ahead, forcing the car off its planned route and down a side branch filled with giant egg-like sacks that appears to have been dug by a gigantic creature. The car emerges on the shore of the Subterranean Sea, and is nearly struck by a lightning from the electrified gas clouds. The finale comes when riders are forced into the fiery heart of an active volcano, where the riders come face-to-face with the giant, tyrannical centipede-like lava monster that has built a nest there, before escaping back to the surface on the wave of an eruption.
History
Journey to the Center of the Earth was originally planned as a freefall ride as part of Discovery Mountain, a former Disneyland Paris concept in place of Space Mountain. Since it was never built, this project reemerged in Tokyo DisneySea with new technology from Test Track, a thrill ride through a GM testing facility at that time.