 Since the 1994 NFL season, the stadium has had a natural grass playing surface.From 1972 to 1993, the stadium had an artificial AstroTurf surface.During the game against the Oakland Raiders on October 13, 2013, Arrowhead Stadium once again became the loudest stadium in the world when the fans set the Guinness Book of World Records record for loudest crowd in an outdoor stadium (137.5 dB), breaking the record set by the Seattle Seahawks just four weeks prior.