Slipknot's first annual music festival, called "Knotfest", was held on August 17, 2012, at Mid-America Motorplex near Pacific Junction, Iowa, and on August 18, 2012, in Somerset, Wisconsin. Deftones, Lamb of God, and Serj Tankian also performed at the festival. The festival shows also debuted a Slipknot museum. On 14, June 2013, Slipknot headlined the Download Festival for a second time. The band performed to roughly 90,000 people and was twice forced to stop the set—once in the middle of a song—to allow the front barricade, which had split open under crowd pressure, to be repaired.