Short answers, pulled from the story.
Metallica officially formed on the 28th of October 1981 with James Hetfield, Lars Ulrich, and bassist Ron McGovney as the original lineup. The band began after Ulrich placed a newspaper advertisement in Los Angeles in late 1981 to find other metal musicians.
Cliff Burton was the original bassist for Metallica until he died on the 27th of September 1986 during a bus accident in Sweden. Jason Newsted eventually replaced Burton after 40 people auditioned for the position.
Metallica released The Black Album in 1991 and sold 650,000 units during its first week in the U.S. The album has since been certified 16 times Platinum and is the 25th-best-selling album in the country.
Metallica sued Napster in 2000 because the peer-to-peer network distributed their entire catalogue without permission. Jason Newsted left the band on the 17th of January 2001 citing private and personal reasons.
Metallica played their first concert in Antarctica on the 8th of December 2013 at an event called Freeze 'Em All. The performance was filmed and released as a live album the same month.
Metallica, Slayer, Megadeth, and Anthrax performed together for the Big Four concerts starting in 2010. Metallica was inducted into the Rock and Roll Hall of Fame on the 4th of April 2009.