A single availability zone can be spread across many physical data centres.
According to this rackspace article, the largest AZ has 5 data centres.
https://blog.rackspace.com/aws-101-regions-availability-zone...
According to this rackspace article, the largest AZ has 5 data centres.
https://blog.rackspace.com/aws-101-regions-availability-zone...
The abstraction behind AZs is what every AZ counts for at least 1 data centre. So for every region there is at least 2 AZs, and every AZ means at least 1 data centre (or 5 in your link).
This just means it's harder to take out a whole region by destroying individual data cetnres. Since most regions consist of 2-5 AZ, and AZs consist of 5+ data centres, that means destroying dozens of data centres.