The 56th annual "Worlds Largest Rattlesnake Round-Up" is March 7th, 8th and 9th at the Nolan Country Coliseum in Sweetwater. In 1958 the Sweetwater Jaycees started this event as a way to control snake populations in West Texas. The over population of rattlesnakes was causing harm to livestock in the Big Country. Today, this event draws more than 40,000 visitors every year. Here's what is happening this weekend.