Photo of the Day 5 November 2007

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.