On October 11, 2011, you may have felt the earth shake—and it had nothing to do with a natural seismic event.

As part of her Let’s Move! campaign to fight childhood obesity, First Lady Michelle Obama urged all Americans to join her in an attempt to break the Guinness World Record for the most people performing jumping jacks in a 24-hour period. And they did it! The previous record was set by 20,000 people. An astonishing 300,265 people across the nation helped Mrs. Obama break the record and make history—while shining a spotlight on the childhood obesity epidemic.