ROSEMONT, IL - MAY 29: A guest learns how to fly in a wind tunnel at the iFly indoor skydiving facility on May 29, 2014 in Rosemont, Illinois. Guests at the facility are introduced to the sensation of free-fall skydiving as they are lifted into the air by fans which generate an upward draft from 80 to 175 miles per hour inside a 14-foot-wide circular chamber. The company operates about 30 similar facilities around the globe which are used for military and competitive skydiver training as well as recreation. (Photo by Scott Olson/Getty Images)