Have you ever wonder how Facebook stores our data, how big Facebook's data center is, what does it look like and how do they manage to keep these servers up and running 24/7? Mark Zuckerberg shares these rare photos of Luleå data center in northern Sweden.

Luleå is a small coastal town just south of the Arctic Circle, and near the top of the world. It’s surrounded by dense forests and icy rivers.

"Look at these racks, the network devices, the cabling. Everything is like reference model!"

- Max Zavyalov, Network Engineer in Edge & Network Services team

Old and obsolete hard drives are crunched, forever protecting privacy. Christer Jonsson is in charge of this important task. "I must be very careful," he says.

The equipment is reduced to its basics so it runs cooler. It can also be easily accessed and repaired quickly. A few years ago, it took an hour to repair a server hard drive. At Luleå, that’s down to two minutes.

The main data hall is so big that engineers move around on scooters.

About 150 people work here, but the data halls are frequently empty. Because of the simplified design, we need only one technician for every 25,000 servers.