Mystery Mine is a Gerstlauer Euro-Fighter model steel roller coaster located at Dollywood amusement park, in Pigeon Forge, Tennessee. The ride, highly themed as a defunct, haunted mining operation from the 19th century, was the single largest investment in Dollywood's history (at the time of its inception), costing US$17.5 million. Designed by German manufacturer Gerstlauer, Mystery Mine was installed by Ride Entertainment Group, who handle all of Gerstlauer's projects in the Americas.While certain sections of Mystery Mine see riders traversing outdoor areas of track, a large portion of the attraction is inside, more akin to a themed dark ride. The rollercoaster features a combination of audio, video, fog, lights and other special effects. At the time, Mystery Mine was the first Gerstlauer Euro-Fighter installation in the United States, and had the steepest ”beyond vertical” drop of any rollercoaster in North America (upon its opening) at 95°; Gerstlauer (among other companies) has since broken that record themselves.