The Swedish wilderness is a fitting place to visit on World Environment Day, for it was in Sweden that the United Nations launched the annual observance 50 years ago, in 1972. This is Rapadalen (Rapa Valley), a 22-mile-long valley in Sarek National Park in the pristine mountains of northern Sweden. Surrounded by steep mountains, the Rapa Valley is considered one of Europe"s most enchanting landscapes. The remote, high-alpine region is beautiful to be sure, but it"s only recommended for experienced and well-equipped hikers. The weather is severe and unpredictable, and there are no accommodations available for tourists.