Robert Louis Stevenson based his fable Treasure Island on the deserted Pacific atoll, and for nearly 200 years, opportunists and adventurers have trawled its shores in search of the world's greatest undiscovered haul, the Treasure of Lima, estimated to be worth up to £160 million.

Now, thanks to Vienna's Thyssen-Bornemisza Art Contemporary, it's official: there really is buried treasure on Isla del Coco. A 21st century cache of 40 works of art lies somewhere beneath Coco's rugged core. It consists of sculpture, LPs, video and sound files from the likes of Ed Ruscha, Lawrence Weiner, Doug Aitken and Marina Abramović - and it's sealed for eternity in a 1x1m bespoke aluminium chest designed by New York architects Aranda\Lasch.

On 13 November a second version of the chest, containing a map of coordinates to the location of the first, goes up for sale at Phillips in New York (current estimate: $150,000-$200,000). Yet the whereabouts should prove as challenging as that of Stevenson's 19th-century predecessor, for the 'map', a steel cylinder printed with 3D-laser sintering technology, has been encrypted with 1,700 figures by a top team of security whiz kids and requires a hacker to unravel it.

In the run-up to the auction, seven clues - created by artist Constant Dullaart, who also designed the map - will be posted across hacker sites, including one exclusive to Wallpaper.com (see gallery).  

But here's the caveat: Thyssen-Bornemisza was granted permission from the Costa Rican government to bury the treasure on Isla del Coco on one condition – proceeds from the auction must go toward a local shark conservation project. Even then, in order to get his hands on the haul, the new owner will need to come over all Long John Silver. He'll have to sail 350 miles from the mainland across rough seas before docking - unauthorised - on the shores of the UNESCO World Heritage Site, and bribe rangers to lead him to the X.

The ship's crew, the artists, curators and rangers signed a blood pact when they hid the chest. All the GPS coordinates were written by hand on paper and then burned. 'Burying the treasure required Fitzcarraldo-esque effort,' says TBA21 founder Francesca von Habsburg. 'Lots of the artists involved were drawn to the project as they wanted to create an exhibition that will never be seen. It's more valuable where it is.'

TAGS: AUCTIONS