[toomuchtodo]

From your link:

"To solve latency, Amazon built Availability Zones on groups of tightly coupled data centres. Each data centre in a Zone is less than 25 microseconds away from its sibling and packs 102Tbps of networking."

25 microseconds at the speed of light (best case, through a vacuum; through fiber is significantly slower) is ~4.7 miles, and based on the quote, that is the furthest they are apart. If your buildings are within 1-2 miles of each other, they're essentially the same facility.

That is not geographically redundant.

[gamegoblin]

Sure, it's not geographically redundant, but nobody in this thread claimed it was. DinkyG disputed that your "one datacenter" claim was false, which it appears to be.