Popcorn is a popular snack food at sporting events and in movie theaters, where it has been served since the 1930s.[24] Cinemas have come under fire due to their high markup on popcorn; Stuart Hanson, a film historian at De Montfort University in Leicester, once said, "One of the great jokes in the industry is that popcorn is second only to cocaine or heroin in terms of profit."[25]