Visit the Arctic vault holding back-ups of great works

High above the Arctic Circle, the archipelago of Svalbard lies halfway between mainland Norway and the North Pole.

Frozen, mountainous, and remote, it's home to hundreds of polar bears and a couple of sparse settlements.

One of those is Longyearbyen, the world's northernmost town, and just outside the settlement, in a decommissioned coal mine, is The Arctic World Archive (AWA) - an underground vault for data.

Customers pay to have their data stored on film and kept in the vault, for potentially hundreds of years.

"This is a place to make sure that information survives technology obsolescence, time and ageing. That's our mission," says founder Rune Bjerkestrand, leading the way inside.

Switching on head-torches we descended a dark passageway and followed the old rail tracks 300 metres into the mountainside, until we reached the archive's metal door.

Inside the vault, stands a shipping container stacked with silver packets, each containing reels of film, on which the data is stored.

"It's a lot of memories, a lot of heritage," Mr Bjerkestrand says.

"It's anything from digitised art pieces, literature, music, motion picture, you name it."

Since the archive's launch eight years ago, more than 100 deposits have been made by institutions, companies and individuals, from 30-plus countries.

Among the many digitised artefacts are 3D scans and models of the Taj Mahal; tranches of ancient manuscripts from the Vatican Library; satellite observations of Earth from space; and Norway's treasured painting, the Scream, by Edvard Munck.

At Piql's headquarters in southern Norway, data files are encoded onto photosensitive film.

"Data is a sequence of bits and bytes," explains senior product developer, Alexey Mantsev, as film ran through a spool at his fingertips.

"We convert the sequence of the bits which come from our clients data into images. Every image [or frame] is about eight million pixels."

Once these images are exposed and developed, the processed film appears grey, but viewed more closely, it's similar to a mass of tiny QR codes.

The information can't be deleted or changed, and is easily retrievable explains Mr Mantsev.

"We can scan it back, and decode the data just the same way as reading data from a hard drive, but we will be reading data from the film."

One key question arising with long-term storage methods, is whether people will understand what has been preserved and how to recover it, centuries into the future.

That's a scenario Piql has also thought about, and so a guide that can be magnified and read optically, is printed onto the film, as well.

Every day more data is being used and generated than ever before, but experts have long warned of a potential "digital Dark Age", as technological advances render previous software and hardware obsolete.

That could mean the files and formats we use now, face a similar fate to the floppy disks and DVD drives of the past.

Many firms offer long-term data storage.

Cassettes of magnetic tape known as LTO (Linear Tape Open), are the most common form, but newer innovations promise to revolutionise how we preserve information.

For example, Microsoft's Project Silica has developed 2mm-thick panes of glass, onto which chunks of data is transferred by powerful lasers.

Meanwhile a team of scientists from the University of Southhampton have created a so-called 5D memory crystal, which has saved a record of the human genome.

That's also been placed in the Memory of Mankind repository, another vault safeguarding historic documents, hidden in a salt mine in Austria.