[4] The national park is dominated by the high mountain chain of the Andes, many lakes, rapid rivers, waterfalls, snow-clad peaks, glaciers and extensive forests.

Francisco de Villagra crossed the Andes through Mamuil Malal Pass and headed south until reaching Limay River in the vicinity of Nahuel Huapi Lake.

[6] In colonial times explorers in the search for the legendary "Ciudad de Los Cesares" visited the zone and Jesuit missionaries coming from Chiloé Archipelago established a precarious mission on the shores of the lake.

[9] A decree of February 1, 1909 recognized that the area needed protection[7] then in 1916 works begun to establish a park and it finally opened in 1922 as Parque Nacional del Sur.

[7] One of the main objectives of the civilizing visions of the National Parks Direction established in 1934 was the urban development of the small settlement of San Carlos de Bariloche on the shores of Lake Nahuel Huapi, which had been connected to the Argentine railway network in 1934.

Bustillo clearly articulated the pretension of building a new orderly city that would act as a bulwark for the colonization of Patagonia, and placed it in a historical line that began with the war of conquest against the Mapuche at the end of the 19th century.

Located at the foot of the Andes Mountains at an altitude of 767 metres (2,516 ft), it measures 544 square kilometres (210 sq mi).

The lake extends 100 kilometres (62 mi) across the border with Chile, and includes many fjords and the Valdivian temperate rain forest.

[19] Its 130 kilometres (81 mi) stretch below the Andes mountains is bounded on the south by Lago Mascardi and on the north by the Villa Traful.

It is also the base for mountaineering trips to 3,554-metre-high (11,660 ft) Mount Tronador (also known as the Thunderer as ice falling produces such sounds) of extinct volcanic origin.

The Cerro Catedral mountain peak is the snow sports center, with many skiing runs, which is 23 kilometres (14 mi) from Bariloche.

[23][better source needed] Other varieties of trees seen in the park are the Chilean cedar (Austrocedrus chilensis), Winter's bark (Drimys winteri), Myrceugenella apiculata, Lomatia ferruginea, Lomatia hirsuta, Alstroemeria aurantica, Fuchsia megellanica, bamboo Chusquea culcou, Mitraria cocinea and Embothrium coccineum.

In the high rain fall zones close to the Chilean border there is profusion of 450-year-old coihue trees (small leaved evergreen beeches).

[19] Animals include river otters (Lontra provocax), southern Andean huemuls (Hippocamelus bisulcus), pudus (small deer), foxes, cougars, guanacos and maras.

[3][4][19] Birds reported include Magellanic woodpeckers, green austral parakeets, geese, ducks, swans, blue-eyed cormorants, Andean condors (Vultur gryphus) and green-backed firecrowns (Saphonoides sephaniodes).

Reported widely since the 1920s, predating Nessie and the book titled The Lost World (Arthur Conan Doyle), Nahuelito is described as “an Argentinean media star.”[25] The park offers many avenues for recreation.

Particular places of interest in this context are the Arrayanes Peninsula, Tronador, Puerto Blest, Victoria Island and the road to the 7 Lakes.

Most of the recreation facility revolves around trekking of high mountain and steep hills[23] apart from rafting, skiing in Cerro Catedral, kayaking in Patagonia Infinita,[26] mountain biking, rock-climbing, kite surfing, canopy, golf at Llao Llao, trekking on a number of routes, ferry services from Villa la Angostura.

[citation needed] Some of the well-developed routes for mountaineering are: The climb to the Thunderer volcano, which has several trails that reach up to the large glaciers; trails to the Tronador (an extinct volcano); the trails that link the San Martin shelter and Manfredo Segre (Black Lagoon); treks to San Martín and Manfredo Segre (Laguna Negra); to Lopez and to the viewpoint of the Stone of Habsburg, the walk of Paso de las Nubes Puerto Frías linking to Pampa Linda; to the valley and the ridge of Mount Rucaco Black Gap; and to Frey and San Martín (Jakob lagoon), which passes by the edge of Cerro Catedral.

The treks are graded under four categories depending on the terrain and the difficulty of climbing rugged hills of heights varying from 200 to 3,000 metres (660 to 9,840 ft).