The Big Four: Live from Sofia, Bulgaria is a live video with performances by Metallica, Slayer, Megadeth, and Anthrax, the "big four" of American thrash metal. The concert took place on June 22, 2010, at the Sonisphere Festival at Vasil Levski National Stadium, Sofia, Bulgaria. It was shown at 450 movie theaters in the United States and over 350 movie theaters across Europe, Canada, and Latin America on June 22, 2010.
Reviews of the DVD were mostly favorable. Websites such as AllMusic and About.com were positive, though Blogcritics gave the DVD a mixed review. The DVD peaked at number one on the United States, United Kingdom, Austrian, and Canadian charts, and also charted on five other charts. It was certified gold in Germany, and provided Slayer with its first platinum certification.