The tour begins at Puerto Bahia Lopez Puerto, 30 km away from Bariloche. We will explore the least-explored, most remote area of the lake, the Tristeza branch of lake Nahuel Huapi, a deep glacial fjord in the southwest of Lake Nahuel Huapi, surrounded by steep mountains and waterfalls. This lake trip was, until now, only accessible by private boats. From the dock we head towards the mouth of the Brazo Tristeza where we can notice how the pristine waters of the lake quieten down, protected by mountains. We cruise into the lake between Cerro Lopez and Cerro Capilla, both steep mountains, to discover numerous waterfalls (especially in the thawing cycle or after heavy rainfall). The forest will gradually set as dense Valdivian Forest, as it's called in certain areas of the Park, where it receives greater amount of rainfall. The west sector branch Tristeza is a Strict Nature Reserve, which aim is to protect the habitat of many plant species and of the Huillín (Lutra provocax), a native aquatic mammal that feeds on crustaceans, fish and shellfish; its image is the symbol of the Nahuel Huapi National Park. The native Huillin can often be difficult to spot in the wild; however, numerous species of birds can be appreciated in the tour, from condors to waterbirds and forest birds. Much of the Tristeza branch coastline is steep cliff and there are very few beaches. In the rocks we can see the effects of glaciers that show the scratch marks caused by the moving ice 5000 years ago. During the cruise, if the weather allows, it is possible to observe the majestic Mount Tronador of 3450 meters, which towers above the landscape with its glaciers and eternal snow. At the end of the peninsula we land and go for a simple hike to the Arroyo Frey waterfall, where the wood slowly transforms into Valdivian rainfores and numerous spectacular waterfalls appear fed by the melting snow. After this we went back to the boat, with the feeling of having been surrounded by mountains and serenity and the opportunity to enjoy nature in its purest form