With the high volume of images, video, and posts being uploaded to Facebook on a daily basis, it made sense for the company to stop relying on third-party data centers and build its own. But it wasn’t enough to just build another massive server farm. When constructing the 330,000-square-foot center, Mark Zuckerberg wanted to make it as energy efficient as possible. That meant the use of massive air conditioners was not an option. Instead, the buildings have huge vents on the sides that pull air in when needed. When air is needed, it goes through a purification and cooling system that consists of fans, filters and water misters before being circulated throughout the building and to the servers. All of that means that the computers use the majority of the energy flowing into the data center.

In 2011, Facebook announced that it was constructing a data center in Lulea, Sweden, its first outside of the U.S. The seaside town, which has an average temperature that ranges from 41 degrees F and 27 degrees F, will allow Facebook to make it even more green than its other centers (the company also has one in North Carolina), by using outside air to cool the servers. In addition, unlike Facebook’s other centers which are powered by energy derived from coal, the Lulea facility will run on renewable energy.