Videos by Timo Arnall | Story by Josh Raab

It’s easy to think of the Internet as an intangible maze of digits, data and domains. But powering everything we do online is a complex network of servers, routers and switches that helps us find dinner recipes, send photos of our children and play the latest mobile game craze. But where is the actual infrastructure that makes all of this possible, and what does it look like?

Our online data lives on seemingly endless racks of servers housed in sleek data centers like this one in Alcalá de Henares, Spain. It’s here that Spanish telecommunications giant Telefonica has built Europe’s largest data center, a 700,000 square foot installation that shows “the hidden materiality of our data” according to photographer and filmmaker Timo Arnall, who produced the project with support from Centre de Cultura Contemporània de Barcelona – CCCB, and Fundación Telefónica.”

Telefonica’s Alcalá data center is one of the most resilient in the world, boasting a staggering 99.995% reliability rate and the coveted Tier IV Gold certification from the Uptime Institute, a data center consortium. Telefonica says the facility is “capable of guaranteeing the highest levels of flexibility, reliability, safety and efficiency.” It’s nearly impossible to design a data center that keeps customers’ data more secure than this one, an achievement that requires state-of-the-art security measures and elaborate systems for power and cooling, all housed in the sleek enclosure you see in these videos.

The Servers

At Alcalá’s heart are the Information Technology (IT) server rooms, which contain racks of servers kept in immaculate sterile environments. Altogether, the Alcalá center stores about 520 petabytes of data at any given time — about 52,000,000 times more than your old iPod. While the servers themselves run almost without a sound, the rooms’ cooling system makes a deafening boom as it works to keep them cool. Each of the 23 IT rooms acts independently to ensure security. Each room consumes 1,200 kilowatts of power, but the plant can quadruple that if need be. The room below has only just begun to be filled and is using a fraction of its potential power.

The Power

Powering Alcala’s IT rooms is no small feat. The facility’s massive main generators are backed up with multiple redundancies to protect against power failures. The main generators are backed up by rows of lead batteries that act as the first line of defense, followed by diesel-powered yellow generators. Should the fuel supply run out, Telefonica has contracted out with energy suppliers with the aim of guaranteeing a steady flow until the power returns to normal. Despite its high energy use, the Alcala center has received the highly coveted Green Building Council’s LEED gold certification, awarded to environmentally sustainable buildings that operate at the highest levels of efficiency.

The Cooling

The Alcala center’s roof is home to the hardest working machines in the building. Rows of enormous “chillers” filter and cool the air before it enters the building, helping to keep the server rooms’ temperature between 66 and 77 degrees Fahrenheit, depending on the outside temperature and the equipment housed in the rooms. The highly efficient cooling infrastructure reduces potential energy consumption in the building by about 75% using an innovative free-air cooling technology that requires almost zero electricity.

The Internet

If you follow a sea of cables through the Alcala building, they will lead you down to the basement through small holes in the wall such as the one below. It’s here that the center connects to the outside world, carrying data headed for Telefonica’s customers and clients across the continent.