Watch: cycling to work through cavernous limestone mines turned into a business park

He calls it YouTube's most unusual bicycle commute. It's a fair claim, too, what with pedaling daily through cavernous limestone mines repurposed as The Springfield Underground, a secure business park in Missouri.

2.5m square feet of warehouses, and who knows how many millions more yet to be developed. The caverns down here are just incredible. THE CAVES.

Here's a slideshow history of the facility, from mining to meat storage.

Vacancies are rare, according to the Springfield News-Leader. Kraft is the largest tenant. Most use it as warehousing and distribution for products that must stay cool; it is always 58 in the caves.

With about a dozen facilities, Missouri is one of the leading states in the underground real estate industry, largely thanks to its mining history and geological makeup - limestone deposits are often covered with a layer of shale, which prevents runoff water from entering old mines. In addition to Springfield Underground, local facilities include The Mountain Complex in Branson and an Americold Logistics facility in Carthage. SubTropolis, a facility in Kansas City which bills itself as "the world's largest underground business complex," has nearly 6 million square feet of space rented.

Here's a video taken coming into a different entrance:

The bike-commute video could be the intro sequence to a video game where the lights suddenly go off and you have to escape the facility, suddenly overrun by a-a-a-a-a-a-a-a-, but not before you've found out what that creepy new tenant was up to and a-a-a-a-a-a-a-a-a-a-a- the a-a-a-a-a-.