With bands like Pearl Jam, U2, Metallica and Nirvana all releasing landmark albums in 1991, the year is one of the most important ones in rock 'n' roll history. Two decades later, the influence of these discs remains as strong as ever. In celebration of the 20th anniversary of one of the biggest years in music, and as part of 'Time Travel' Week, here's Ultimate Classic Rock's list of the 10 Best 1991 Rock Albums: