The Selvaggio Blu (Wild Blue) is a trekking route in the territory of the district of Baunei (Sardinia). It was conceived in 1987 by Mario Verin, (photographer and alpinist) and Peppino Cicalò (architect), President of the Nuoro section of the Italian Alpine Club. The itinerary extends for over 40 kilometers (approximately 25 miles) from the touristic port of Santa Maria Navarrese (Baunei) to the beach of Cala Sisine (Baunei). It takes on average 4 days to complete. The Selvaggio Blu is considered one of the last wild trekking routes of the Mediterranean because, for the major part of the itinerary, it can only be accessed by boat or by following the path along the coast of the Gulf of Orosei. Verin and Cicalò used the name 'Selvaggio Blu' to reflect the main characteristics of the journey: "Selvaggio" to reflect the wildness and pureness of the experience, and "Blu" because the trek goes along the coast, where the color of the sea and the sky is predominant. Location The Selvaggio Blu is located entirely in the territory of the district of Baunei which extends for 211.9 km2 on the east coast of Sardinia, in the province of Ogliastra. The Baunei area is considered one of the wildest in Sardinia, going from the coastal town of Santa Maria Navarrese and traversing Limestone plateaux and coastal scenery to the beach of Cala Luna. It contains all the main centers on the route, including: Santa Maria Navarrese, Pedra Longa, Portu Pedrosu, Cala Goloritzè, Su Feilau, Cala Sisine and also all the centers included in Selvaggio Blu variations: Cala Mariolu, Cala Biriala; S'Istrada Longa, Grotta del Fico and the plateau of Golgo. Geology Selvaggio Blu has a strategic location to see the geological history of Sardinia, as it is located 40 km along the coast. There are several important geology observations on Selvaggio Blu's hiking route which can be reached both by land and sea. In the northern part of Santa Maria Navarrese, hikers have the possibility to move along a section with fractured granite from the Palazoic age, where rocks are several meters thick. This area contains some of Sardinia's oldest rocks, covered with layers of Cambrian-Ordovician metasandstones, phyllites and quartzites. In Pedra Longa the section with granite ends, and there is a transition to the limestones, which are a common feature of the Gulf of Orosei coast. Because of climate changes the limestone