Avengers: Age of Ultron is a 2015 American superhero film based on the Marvel Comics superhero team the Avengers, produced by Marvel Studios and distributed by Walt Disney Studios Motion Pictures. It is the sequel to 2012's The Avengers and the eleventh film in the Marvel Cinematic Universe (MCU). The film was written and directed by Joss Whedon and features an ensemble cast that includes Robert Downey Jr., Chris Hemsworth, Mark Ruffalo, Chris Evans, Scarlett Johansson, Jeremy Renner, Don Cheadle, Aaron Taylor-Johnson, Elizabeth Olsen, Paul Bettany, Cobie Smulders, Anthony Mackie, Hayley Atwell, Idris Elba, Stellan Skarsgard, James Spader, and Samuel L. Jackson. In Avengers: Age of Ultron, the Avengers fight Ultron, an artificial intelligence obsessed with causing human extinction. The sequel was announced in May 2012, after the successful release of The Avengers. Whedon, the director of the first film, was brought back on board in August and a release date was set. By April 2013, Whedon had completed a draft of the script, and casting began in June with the re-signing of Downey. Second unit filming began in February 2014 in South Africa with principal photography taking place between March and August 2014. The film was primarily shot at Shepperton Studios in Surrey, England, with additional footage filmed in Italy, South Korea, Bangladesh, New York, and various locations around England. While in post production, the film was converted to 3D and over 3,000 visual effects shots were added.