Stage 3 of the Dolomites World Heritage Geotrail II leads from the Karer Pass/Passo Costalunga through the heart of the Rosengarten mountain range, past the reef of the Schlern and on to the Tierser Alpl Mountain Refuge. The hiker will cross different environments of the Triassic atoll: the deep sea (Karerpass/Passo di Costalunga), the underwater escarpment (Rosengarten Massif) and the inner lagoon (Torri del Vajolet).