We're set up across multiple AZs in the affected region, and all we had was a few minutes of failed requests to one AZ until our systems automatically shifted a

We're set up across multiple AZs in the affected region, and all we had was a few minutes of failed requests to one AZ until our systems automatically shifted all the traffic to another. Even the major day-long outage last year because we had (at the time) not really spread ALL our core systems across multiple AZs. We just re-launched those systems on another AZ and everything was up and running again. Which outages have affected multiple AZs?