Over 100 people at the Pikes Peak regional airshow in Colorado got sick from the heat on Saturday.
The lack of shade and free water, combined with the sweltering 96-degree temperatures, led to dehydration, heat exhaustion, and even heat stroke.
Medical tents were set up to treat those affected, with five people being transported to hospitals.
The airshow organizers have urged people to bring water bottles, hats, and umbrellas for future events.