Lanín is an ice-clad, cone-shaped stratovolcano on the border of Argentina and Chile. It forms part of two national parks: Lanín in Argentina and Villarrica in Chile. It is a symbol of the Argentine province of Neuquén, being part of its flag and its anthem. Although the date of its last eruption is not known, it is estimated to have occurred within the last 10,000 years.

The ascent is regulated by the management of Argentine National Parks and the Argentine National Gendarmerie, and is relatively simple, but many deaths have occurred due to lack of responsibility and caution of the climbers. The nearest towns, usually employed as a base for climbers, are Pucón in Chile and Junín de los Andes in Argentina.

There are two paths to the summit: one on the north, starting at 1,200 above mean sea level near Lake Tromen and the international Mamuil Malal Pass, accessible via Neuquén's Provincial Route 60; and one on the south, starting beside Lake Huechulafquen, accessible via Provincial Route 61.

credited to wikipedia