On 20 April 1992, The Freddie Mercury Tribute Concert was held at London's Wembley Stadium to a 72,000-strong crowd. Performers, including Def Leppard, Robert Plant, Guns N' Roses, Elton John, David Bowie, George Michael, Annie Lennox, Seal, Extreme, and Metallica performed various Queen songs along with the three remaining Queen members (and Spike Edney.) The concert is listed in the Guinness Book of Records as "The largest rock star benefit concert", as it was televised to over 1.2 billion viewers worldwide, and raised over £20,000,000 for AIDS charities.

When was the Freddie Mercury Tribute Concert held?