The last time U2 went on tour, they revisited their landmark 'Joshua Tree' album. On their current trek, they appear more interested in looking back on other corners of their classic catalog.
U2 bankrolled the biggest concert stage ever built for their 360 Tour in 2009, and now one of the record-setting structures assembled for those shows has found a permanent new home.
Guns N' Roses' tour with Metallica was the hard rock live event of the early '90s, but it might have been followed up with an even bigger concert collaboration.