Photo of the Day 38

Royal Ascot Racecourse, England, 2007

Photograph by Peter Essick

In high spirits, a well-dressed crowd at Ascot Racecourse near London celebrates a day of horse races with singing and patriotic flag-waving. Scientists study the behavior of animal swarms, such as schools of fish, to predict the way humans might behave in such densely packed groups.

(Text adapted from and photo shot on assignment for "Swarm Theory," July 2007, National Geographic magazine)