April 12, 2001: The Toronto Blue Jays cancel their game against the Kansas City Royals after the SkyDome roof jams and debris falls onto the field.
SkyDome had been in commission since 1989, but this was the first time the roof had problems.
"You've got 11,000 tons of roof up there moving, and even when you're closing it or opening it slowly, there's a lot of momentum, and if those control systems fail, you're going to have a little bit of a problem," a SkyDome executive told the Associated Press at the time.
This is how the retractable should look when it open or closes.
The roof was fixed, and the Blue Jays only had to postpone one game.