Dean’s Downtown Underground, near downtown Kansas City, started out as a railroad tunnel project in the 1870s, and was excavated as a limestone mine after that. It was developed into underground commercial space starting in 1958, by local developer Lester Dean, who had amassed a fortune salvaging surplus WW2 ships and machinery. It opened officially in 1966, with a Fred and Wilma Flintstone-themed caveman party, though Hallmark cards had set up in the space as early as 1961. The Dixie Cup paper cup company was also an early tenant. 1.2 million square feet is now developed, and it has a variety of tenants.