AZs are physically located near each other, usually within a small enough radius that they could be all impacted by the same natural disaster. In some cloud pro

AZs are physically located near each other, usually within a small enough radius that they could be all impacted by the same natural disaster. In some cloud providers and regions, AZs are simply different parts of the same building (IIRC one of the Japan regions of Azure was essentially this, but don't quote me). And evidently, the share some infrastructure. At a previous job where we needed to always be up, our disaster recovery plan assumed that the us-east-1 site had been hit by a meteor (not literally, but that's how we explained it to each other to put ourselves in the mindset.)