Flying instructor David Schnaible (R) teaches wind tunnel flying to nine-year-old Liam Harrison at the iFly indoor skydiving facility in Rosemont, Illinois on May 29, 2014. Guests at the facility are introduced to the sensation of free-fall skydiving as they are lifted into the air by fans that 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 that are used for military and competitive skydiver training as well as recreation. By Scott Olson/Getty Images.