I count myself as one of the lucky few who have ever been inside a Google datacenter. I went to one a few years back that was in the middle of the country (won't say where for security purposes) and the experience was quite extraordinary. Everything that is mentioned in the video above is true. Google really does employ the best of the best server technicians from around the globe to maintain the data infrastructure needed to serve websites, email, and secure documents anywhere around the world.
The one thing I remember very fondly was the amount of security present at one of these datacenters. Given the sensitive nature of what's stored inside Google datacenters (everything from websites, to email, to government data and much, much more) it would make sense that the security measures in place would seem like something out of Mission Impossible. It's a fortress, with cameras, checkpoints, and security personnel at every turn. It's both exhilarating and intimidating at the same time.
I wish I could go back someday. I have no idea if I ever will be invited back, but we'll see I guess.
Here's one more video about security at Google datacenters.