|Location||Kansas City, Missouri, United States|
SubTropolis is a 55,000,000 square foot (5,060,000 m³), 1,100-acre (4.5 km2) manmade cave in the bluffs above the Missouri River in Kansas City, Missouri, United States, that is claimed to be the world's largest underground storage facility.
Dug into the Bethany Falls limestone mine SubTropolis is at places 160 feet (49 m) beneath the surface. It has a grid of 16 ft (4.9 m) high, 40 ft (12 m) wide tunnels separated by 25 ft (7.6 m) square limestone pillars created by the room and pillar method of hard rock mining. The complex contains almost seven miles (11 km) of illuminated, paved roads and several miles of railroad track. Currently 5,000,000 square feet (460,000 m³) is occupied and 10,000,000 square feet (920,000 m³) are "improved." About 3.2 acres (13,000 m2) of available space are added each year as active mining continues.
The mine naturally maintains temperatures between 65 and 70 degrees Fahrenheit (18 to 21 °C) year-round. The United States Postal Service and the United States Environmental Protection Agency lease spaces within SubTropolis, the United States Postal Service for its collectible stamp operations and the U.S. Environmental Protection Agency for their Region-7 Training and Logistics Center.
On the north edge of the complex Hunt developed the Worlds of Fun and Oceans of Fun amusement park complex. Hunt's extensive business dealings in Clay County contributed to the Chiefs having their NFL Training Camp at William Jewell College in Liberty, Missouri until 1991.
Other facilities like SubTropolis exist although not on the same scale, such as the abandoned mine in Butler, Pennsylvania used by Corbis and the US Federal Government for secure storage. As the room and pillar mining method is used to extract limestone throughout the Midwest, many companies are looking at ways to utilize the hundreds of millions of square feet created in this manner for everything from mushroom farming to crude oil stockpiling.
SubTropolis is used by around 50 businesses and organizations, including:
- Grantham University
- Vanguard Packaging
- United States Postal Service
- Hallmark Cards
- Paris Brothers
- Clore Automotive
- EarthWorks/Learning Exchange
- Safeway Stores
- Elliott, Monica. "Subterranean sprawl: at SubTropolis, what lies beneath is a land of industrial opportunity", "Industrial Engineer", 1 December 2003.