Documentary filmmaker David Maysles and his brother, Albert Maysles, played important roles in the development of cinema verité, designing highly portable cameras and sound equipment that gave filmmakers minimal intrusion while documenting their subjects. Before teaming up with his brother in 1957, Maysles worked as a production assistant on two Marilyn Monroe features. The Maysles brothers formed their own production company in 1962 and went on to make many documentary films for both the big screen and television. Their best-known documentaries are Salesman (1969) and Gimme Shelter (1970); the latter was a disturbing, controversial chronicle of a Rolling Stones concert during which four people were killed by the Hell's Angels hired by the band to keep fans off the stage. The Maysles captured one of those brutal murders on film, repeatedly showing it throughout the documentary. In 1974, David Maysles was nominated for an Academy Award for Valley Curtain, the first of three documentaries looking at the life and work of idiosyncratic outdoor artist Christo. He continued working until his death on January 3, 1987; in addition to his documentary Vladimir Horowitz: The Last Romantic, which was released the same year, another project, Beatles: The First U.S. Visit, was released posthumously in 1991.