30 years ago: Two World Championship matches in the same year
1993 was a particularly memorable year in chess history. Short and Kasparov had decided to leave FIDE and organise their World Championship match on their own, and FIDE, with its then President Campomanes, then organised an alternative World Championship match with Karpov and Timman. But this was not under a good star. During the opening ceremony pyrotechnics set fire to a banner on the stage.
Source: chessbase.com