Rare photos of Facebook's massive, futuristic data centre near the Arctic Circle

Sporting more than 1.71 billion monthly active users, Facebook has multiple massive data centres to store and serve up users' constantly growing collection of updates, likes, photos, video and other precious data every day.

To give people a glimpse into the advanced technology that goes into supporting the social media giant, CEO Mark Zuckerberg has announced that he will begin sharing photos of the company's new, advanced technologies being built around the world.

Starting with Facebook's Luleå data centre in northern Sweden, located 70 miles south of the Arctic Circle, Zuckerberg published a series of rare photos of the mammoth facility in a post on his Facebook page on 28 September.

Tucked away in the dense forests of northern Sweden, Zuckerberg said the centre is a "key part of our global infrastructure" that uses "a variety of local natural resources to increase efficiency and save power".

"It's typically pretty cold," Zuckerberg wrote. "The temperature in the area is below 50 degrees most days, so we use large fans to pull in the outside air to naturally cool the thousands of warm servers that line the centre's broad hallways."

When the temperatures drop to -30 degrees in the winter, he said the situation is reversed where the building is warmed with the heat emitted from its tens of thousands of servers.

Despite its mammoth size, only 150 people work in the data centre with just one technician needed for every 25,000 servers due to its "simplified design". Zuckerberg said the facility's main hall is so huge that engineers usually move around the frequently empty, steely halls on scooters.

Zuckerberg said a dozen hydro-electric plants operating on nearby rivers serve as a reliable, renewable power source for the futuristic data centre that was opened in 2013 as Facebook's first data centre outside of the US. He added that the entire system is 10% more efficient and uses nearly 40% less power centres than traditional data centres that typically voraciously consume vast amounts of energy and give off waste heat.

"Inside, the main building is the size of six football fields," Zuckerberg said, adding that nearly all the technology in the facility, from its servers to its power distribution systems, is based on Open Compute Project designs.

"A few years ago, it took an hour to repair a server hard drive. At Lulea, that's down to two minutes," he said.

"You probably don't think about Luleå when you share with friends on Facebook, but it's an example of the incredibly complex technology infrastructure that keeps the world connected," Zuckerberg said.

Earlier this month, Facebook revealed plans to open its next data centre in Los Lunas, New Mexico, that will come online in late 2018 - its seventh data centre in total and fifth stateside site. The social media network also has data centres in Clonee, Ireland; Forest City, North Carolina; Prineville, Oregon; Fort Worth, Texas and Altoona,Iowa.

To cut down on energy costs and address the persistent issue of data centre cooling, Microsoft is testing an underwater data centre as a cost-effective and environmentally friendly solution using seawater as a coolant. Google is also using its DeepMind artificial intelligence (AI) technology to more efficiently manage its data centres' energy consumption, cutting down on its energy use by 15% using a machine-learning algorithm.