Underground
Built in 1996 by Custom Coasters International, The Underground was the first modern indoor wooden roller coaster.  It remains the world's only totally enclosed wood coaster.  Despite its name, the coaster is actually all above ground level, but it is enclosed by this green building.  It is themed like an old mine.

The mine train's track is a little over 900 feet long.  It features two chain lifts, the tallest of which is only 13 feet tall.  Most of the ride consists of track gradually sloping downward.  The coaster makes a couple little dips of a foot or two, but there is never a large drop anywhere.  Because of this, the train mostly moves at a walking pace.  In fact, there is some debate as to whether the ride is a dark ride or a roller coaster.  Since it is built by a coaster company, and since it uses gravity to travel nearly all of the track, I consider it a roller coaster.

©2020 Joel A. Rogers.