Rainbow performed on this day in 1980 at the Sporthalle in Cologne, Germany.
Rainbow were at this time on their Down to Earth Tour, undertaken to support the album of the same name. The group had already performed several dates in Germany on the tour, though in between those and this concert they had toured in other places.
This particular concert is notable in Rainbow history because later in the set, bassist Roger Glover collapsed onstage. Glover had not been a regularly touring musician since 1973, and had largely left performing after having been fired from Deep Purple. The following day, the group cancelled a concert, reportedly because Glover was ill.
This concert is known to have been recorded, and is in circulation online.
I talk more about the Cologne Sporthalle, the venue at which the group performed, here.