The name comes from Mapudungun, the language of the Mapuche, and is usually read as malal-hue - roughly "place of corrals" or "place of rocky cliffs." Long before any observatory, this was open indigenous territory, home to Pehuenche, Puelche and Mapuche peoples who moved across the high country and traded along its passes. The land stayed largely beyond colonial control until the Argentine state's campaigns of the late nineteenth century. The town that grew here is now the seat of the largest and emptiest department in Mendoza Province, a place defined as much by what surrounds it - volcanoes, lava fields, salt lagoons - as by the modest grid of streets at its center.

Malargüe calls itself home to the world's largest cosmic-ray observatory, the Pierre Auger, and the claim shapes the town. The visitors' centre stands at the northern end of the city on Avenida San Martín. Drive in on ruta 40 and you pass through the edges of the array without quite realizing it: white tanks, each a sealed barrel of ultra-pure water wired with electronics and solar panels, scattered across the steppe in a vast triangular grid. They stretch for an hour's drive at highway speed. Ask at the centre and, if researchers are on site, you may find yourself talking with a physicist who flew in from Europe or the United States to study particles older than the Earth.

The country around Malargüe is a geologist's daydream. To the south lies La Payunia, a reserve dense with volcanic cones and black lava flows, where a careful driver can reach the base of Volcán Payún and herds of guanaco-like animals cross the track. Closer to town are the Pozos de las Ánimas, a pair of great sinkholes, and the Caverna de las Brujas - the "witches' cave" - which must be booked in advance back in town. After heavy rain the surrounding pampa floods, and shallow lagoons fill with flamingos and ibises just a few kilometres out, turning a seemingly barren plain into a birdwatcher's reward.

In winter the town fills a different role. Malargüe is the nearest base for Las Leñas, one of South America's premier ski mountains, an hour or so up the road. Skiers stay here because the hotels are cheaper and many of them throw in discounted lift passes. The same valleys lead toward Cerro Sosneado - at 5,189 metres, the southernmost peak in the Americas to top 5,000 - and on toward the free, half-ruined thermal baths at El Sosneado. Whether you arrive for the snow, the science, or the volcanoes, Malargüe rewards the kind of traveler willing to drive a long way into big, quiet country and look closely at what is there.