Boasting 5 miles of trails, ramps and obstacles, this cavernous subterranean space sits 100 feet underground and totals 320,000 square feet. The wide-open footprint and copious mounds of dirt, able to be endlessly reformed into new types of terrain, lend themselves to this particularly fitting form of adaptive reuse.

Located in Louisville, Kentucky, and open as of yesterday, the Mega Underground Bike Park gains a number of advantages from being far below the surface, including a relatively consistent temperature and protection from wind, rain and other weather (without the typical costs of constructing a building to house these activities).

Originally a limestone mine, there were plans to create a highs-security business park in the space – while there are a few businesses actually occupying other parts of the underground complex of caves, the big idea fell through, replaced by a plan to create zip lines, challenge courses and now the biggest interior bike park on the planet.

Currently the space offers 45 trails with differing degrees of of difficulty as well as clever additions like cargo containers turned into ramps and overpasses. Most of the materials needed, though, were already in place – it was mainly a matter of lighting, accessing and shaping the space.

From their website: “Are you ready to experience a one of a kind Underground Bike Park? Over 320,000 square feet including over 45 trails, Jump Lines, Pump Tracks, Dual Slalom, BMX, Cross Country and Single Track all in a former limestone cavern 100 feet sub-surface. Enjoy the comfort of our 60 degree temperature year round. Come experience what the buzz is all about. You simply won’t believe what you see.”