The Big Four: Live from Sofia, Bulgaria
The Big Four: Live from Sofia, Bulgaria is a concert video with the bands Metallica, Megadeth, Slayer and Anthrax in it. These bands are known as the "Big Four" of American thrash metal. The concert happened on June 22, 2010, at the Sonisphere Festival (a rock music concert) in Sofia, Bulgaria. It was shown at over 400 movie theaters in the United States, and over 300 theaters in other countries.