More than 2,500 have taken part in O'Hare International Airport's 5K on the Runway race to benefit a program to help wounded U.S. military service members.
Saturday's event included runners of all ages as well as aviation enthusiasts eager for an up-close experience on a runway at 1 of the world's busiest airfields.
The 5K course took participants underneath the wings of a United Airlines plane. The runway was closed for six hours, but no flight operations were disrupted.
There was also live music and food.
The event benefited the Wounded Warrior Project, which raises awareness and enlists the public's help in aiding injured service members.
A United Airlines official presented the organization with a $25,000 check.