Some people might think about the Internet as something ethereal that floats around the sky like a cloud, but the truth is that Internet actually occupies physical space in buildings known as data centers, filled with thousands of computer servers which are interconnected by lots of fiber optic cables that allow data to travel back and forth around the world. So every time you upload a selfie on Instagram, upgrade your Facebook status or tweet, you are using a data center.

Here is a list of the data centers that earned a superlative, either for their energy-efficiency green efforts or their size.

The first

Back in the late 1950s, IBM and American Airlines partnered to develop what would become the beginning of data centers: a computer system that would help the airline to automate its booking reservation method. By 1960 they had created the Semi-automated Business Research Environment (SABRE), which was installed in two IBM 7090 computers and set in a computer center in Briarcliff Manor, New York.

The weirdest

Pionen White Mountains is located in Stockholm inside a former nuclear bunker that operated as a command center during the Cold War. It may look as the headquarters of a movie villain, but it belongs to the Swedish ISP Bahnhof. CEO John Karlung said in an interview that the design was inspired by 70’s movies such as Silent Running, Star Wars and James Bond.

Data center design is an important issue because when a company decides to build this kind of enterprise has to be aware of factors such as location, capacity to be expanded and handle more data, power distribution, construction cost and so on.

The most social ones

Have you ever wondered where your photos go? Social media companies like Twitter, LinkedIn and MySpace have built their own data centers to store the big quantities of information, pictures, subscriptions, videos or audio-files they have to manage daily. But there’s one social network that owns four of the busiest data centers in the world and is building a new one. If you are thinking about Facebook, you are right.

Facebook is the largest social network and the most popular web site. With more than one billion active users and 1 trillion page views monthly, Facebook has 9% of all the Internet’s traffic. Facebook facilities in Oregon and North Carolina measure roughly 300.000 square feet and its thousands and thousands of servers store about 300 Petabytes in pictures.

The greenest

Believe it or not, Internet usage can damage the environment. By 2013 it was estimated U.S data centers consumed 91 billion kilowatt-hour. Worldwide data centers are responsible for 2% of all global carbon emissions and they also need significant amounts of water to cool their servers. But some data centers are designed in a way that minimizes energy consumption and environmental impact.

Portugal Telecom found a solution locating its newest data center in Covilhã, the coldest location in the Iberian country, which allows them to cool the servers with natural air 99% of the year, turning the air conditioners on just 4 days a year. It also features a rain water collection system and photovoltaic solar power generators, reducing energy waste in about 30%. All these actions earned it the award of greenest data center of 2014.

The largest

The 350 E. Cermak, located in Chicago, is currently the largest data center in the world, with a size of 1.1 million square feet, roughly the equivalent of 23 football fields. It is maintained by more than 50 generators fueled by several diesel tanks of 30.000 gallons. But 350 E. Cermak is about to be defeated by the Range International Information Group, a 6.3 million feet data center scheduled to be finished in 2016.

According to the the International Data Corporation, data centers occupied 1.58 billion square feet of space worldwide by 2013, a digit is expected to grow to 1.94 billion square feet by 2018. Data centers are facilities that range from small computer rooms to enormous buildings in which several football fields could easily fit side by side.

Did we miss an amazing data center? Tell us and we will add it!