The Dolomites were listed as Unesco Natural Heritage sites on 26 June 2009. Formed some 250 to 50 million years ago as coral reefs at the bottom of the ancient Tethys Sea, the "Pale Mountains", as they were once called, now soar as rugged towers above rolling Alpine meadows.
Six South Tyrolean nature reserves have been included in the list of Natural Heritage sites: Bletterbach Gorge, Latemar, Trudner Horn Nature Reserve, Puez - Geisler Nature Reserve, Schlern - Rosengarten Nature Reserve, Fanes - Sennes - Prags Nature Reserve and the Sexten Dolomites Nature Reserve with the Tre Cime di Lavaredo.
In Veneto the World Heritage property includes the landscape around the Pelmo and Croda da Lago, and the area between Cadore, Zoldano and Ampezzo. In Trentino the Marmolada, Pale di San Martino and the Brenta Dolomites. The Friulian Dolomites in Friuli, with Oltre Piave the most easterly part in the italian provinces of Pordenone and Udine.