Or rather an afternoon and two nights in front of it.
Last summer scenes for the new Mission: Impossible movie were being filmed in Vienna and I thought I'd go and see if there was anything to see.
I think it was on the first day that I got to watch them film the Police arriving in front of the Opera. (And not like in the pictures here, but with lights and sirens and the whole shebang.)
Apparently I missed all the fun parts of that day though, as I'd read the day after that they'd also been filming a car explosion.
The next day I had more luck.
The Ring (the street in front of the Opera) was closed off properly this time, with spectators having to go quite a way down the side streets. We got to watch the cars and tram go back and forth for some time.
I hadn't expected to actually see any of the main actors, but after the stunt people had tested the rig for the stunt, Tom Cruise actually appeared on the roof waving at the onlookers. (And presumably the lady jumping off the roof with him was Rebecca Ferguson, but I didn't even know her name back then, so that didn't get me as excited as seeing Mr Cruise.)
Here, have a crappy gif of the action: