Tornado partner Bill McNutt decided to merge their team with the Tampa Bay Rowdies franchise, while retaining a minority stake in the Florida club. Two years later, along with Rowdies principal George Strawbrige, they sold the Rowdies to local investors. The move effectively ended Hunt's ties to the NASL a year before the league itself finally collapsed in 1984. Major League Soccer Hunt returned to soccer as one of the original founding investors of Major League Soccer, which debuted in 1996. He originally owned two teams: the Columbus Crew and the Kansas City Wizards (now Sporting Kansas City). In 1999, Hunt financed the construction of the venue now known as Mapfre Stadium, the second, and first since 1913, of several large soccer-specific stadiums in the USA. In 2003, Hunt purchased a third team, the Dallas Burn (now FC Dallas), after announcing that he would partially finance the construction of their own soccer-specific stadium. On August 31, 2006, Hunt sold the Wizards to a six-man ownership group led by Cerner Corporation co-founders Neal Patterson and Cliff Illig. Tennis In 1968, Hunt co-founded the World Championship Tennis circuit, which gave birth to the Open Era of tennis. He was inducted into the International Tennis Hall of Fame in 1993. Business ventures outside sports Amusement parks and caves Hunt was the founder of two theme parks in Kansas City: Worlds of Fun and Oceans of Fun, which opened in 1973 and 1982 respectively. The two parks were an outgrowth and adjoined a vast industrial park he developed in the bluffs above the Missouri River in Clay County, Missouri. Immediately south of the Hunt-founded parks is the Hunt-developed SubTropolis, a 55 million-square-foot (5.06 million m2), manmade limestone cave which is claimed to be the World's Largest Underground Business Complex (TM). 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. Hunt Brothers Silver speculation During the 1970s and early 1980s, brothers Nelson Bunker Hunt and William Herbert Hunt attempted to corner the silver market. They began buying silver in the early 1970s. By the end of 1979, their ownership of one-third of the world silver market caused the price to rise from $11 an ounce in September 1979 to $50 an ounce in January 1980. In the last nine months of 1979, the brothers profited by an estimated $2