The road through the narrow, steep gorge was opened in 1913 but has been cut off many times by landslides. The most spectacular of these occurred during the First World War and resulted in the formation of a lake in gorge.
 
The Sentinel, a Land-Art installation, is part of the Refuge d'Art Project (a Land-Art-Installation Project themed on finding refuge and sanctuary in the natural surroundings of the mountains), which consists of a route, an artwork trail of almost 150km through the Haute-Provence Geopark, imagined and created by Andy Goldsworthy, a British artist and a major figure of Land-Art.

The route of the walking-trail links the three Sentinels : one at Authon, one at Barles and one at Tartonne.  The walking route is dotted with abandoned rural buildings restored by incorporating an original piece of Land-Art artwork, its creation inspired by the place and surroundings.  The Barles Sentinel was the first piece of this masterpiece in 1999.
The gorge is also home to the piece of Land-Art titled, "The Garden Without a Gardener", by Herman de Vries.

For more information: www.refugedart.fr and www.musee-gassendi.org