Sentinel, Andy Goldsworthy, 1999, Col du Defens, Alpes de haute Provence, France "The work Sentinels, which is part of the Refuge d'art project, is a journey through the Dignois region, at the foot of the Southern Alps. Such a project associates art, nature and the territory. The three Sentinels are stone cairns, one for each of the three valleys of the Haute-Provence Geological Reserve.