Lars Ulrich is a Danish musician, songwriter, actor, and record producer. He is best known as the drummer and co-founder of the American heavy metal band Metallica. The son of tennis player Torben Ulrich and grandson of tennis player Einer Ulrich, he also played tennis in his youth and moved to Los Angeles at age 16 to train professionally. However, rather than playing tennis, Ulrich began playing the drums. After publishing an advertisement in The Recycler, Ulrich met vocalist/guitarist James Hetfield and formed Metallica.
Said upon discovering that, during the 2003 invasion of Iraq, uncooperative prisoners were exposed to the Metallica song "Enter Sandman" for extended periods by American interrogators.
Source: [Maddow, Rachel, Rachel Maddow, Lars Ulrich, Metallica's Lars Ulrich joins Maddow, The Rachel Maddow Show, MSNBC, April 27, 2009, https://www.youtube.com/watch?v=iuNfAFOv2F4&t=6m19s, April 18, 2015]
