The rugged Sierra de la Ventana mountain range, 550km southwest of Buenos Aires, is the principal attraction of southern Buenos Aires Province. Running from northeast to southwest for 100km or so, the sierras’ craggy spine forms a surprising backdrop to the serene pampas and provides the best opportunities in the province for walking and climbing. The range is named after one of its highest points, the Cerro de la Ventana, a 1136m peak pierced by a small “window” (ventana in Spanish); it’s located within the Parque Provincial Ernesto Tornquist, bisected by the RP-76, the main highway through the sierras. There are plenty of options for accommodation in the area: as well as a base camp within the park, the nearby village of Sierra de la Ventana offers the best setup for visitors; it is situated around 30km southeast of the main park entrance.
Formed principally of sedimentary rock created during the Paleozoic period, the range is notable for its intensely folded appearance and its subtle grey-blue and pink hues. Though the harsh peaks may appear barren, the area supports an amazing range of wildlife, including pumas, foxes, guanacos, armadillos, vizcachas (rabbit-like rodents appreciated for their meat) and copper iguanas. The latter are named for their distinctive colour and are one of over forty species endemic to the region.
The province’s highest peak, Cerro Tres Picos (1239m), juts from private land 6km south of Villa Ventana. It is less photogenic than Cerro de la Ventana, but its height, combined with its distance from the nearest base, makes it a more substantial hike. It is usually done as a two-day trek, overnighting in a cave on the way up. The route passes through land belonging to the Germanic Estancia Funke (t0291 494 0058, wfunketurismo.com) and you must go with a guide provided by the owners.