Data centers are typically shrouded in secrecy because they are the brains behind tech companies.

But not Google. The search giant has shared with the world photos that lift the veil off its massive and beautiful data centers around the world, in places both domestic, including Iowa, Oregon, Georgia, South Carolina, and Oklahoma, and abroad, in Finland and Belgium.

Google says when you're on its website, you're accessing one of the most powerful server networks in the known universe. Looking at these images, it's hard to disagree.

Google has been working on building its data centers for over 12 years. The search giant's centers are efficient, take advantage of renewable energy, and are as environmentally friendly as possible.

The following tour is a glimpse inside a few of Google's data centers, which it calls the "physical internet."

Kevin Smith wrote an earlier version of this post.