Manchester City head to Bayern Munich on Wednesday with a Champions League semi-final spot firmly in their grasp.
Bayern host the Premier League champions needing to overturn a three-goal deficit - something only achieved on three previous occasions in the competition - after losing the quarter-final first leg 3-0 at Etihad Stadium.
But history shows the improbable is not impossible.
Before Bayern look to upset the odds, we revisit some of the greatest comebacks in Champions League history.
Ajax 2-3 Tottenham (semi-final second leg, 8 May 2019)
Aggregate 3-3: Tottenham win on away goals
Tottenham travelled to Ajax for the second leg of their semi-final trailing 1-0, and things went from bad to worse in Amsterdam when Matthijs de Ligt and Hakim Ziyech put Ajax 3-0 ahead on aggregate before the break.