Neuquén lives by water in a place that has almost none. The city sits in a narrow valley where the rivers carry Andean snowmelt across the otherwise parched Patagonian meseta, and canals fan that water out into orchards and poplar windbreaks. Step beyond the irrigation and the land changes abruptly. North of downtown rise las bardas, the eroded badland hills of stony ridges and small canyons that mark the true face of the region: semi-desert, scoured by spring winds, scattered with steppe scrub. From the Balcón del Valle overlook at the top of Avenida Argentina, the contrast is almost violent. On one side, the orderly green ribbon of the valley with its fruit trees and river beaches. On the other, dun-colored hills rolling away toward the horizon under an enormous, cloudless sky.

The geologists named it Vaca Muerta, the dead cow, a slab of dark shale laid down between the Late Jurassic and Early Cretaceous when this whole basin lay beneath a shallow sea. It covers some thirty thousand square kilometers, the largest shale play known outside North America, and it holds one of the world's great reserves of oil and gas. For a century the rock was simply there, useless, until fracking made it reachable. The boom arrived like a tide. Construction cranes, new neighborhoods, restaurants and craft-beer bars, workers streaming in from across the country. Neuquén had spent its first hundred years as a quiet capital. It is spending its second as a frontier town, with all the energy and friction that word implies.

Neuquén exists because of a decision about a train. Founded in 1904, the settlement won the title of territorial capital largely because the railway from Bahía Blanca had reached the confluence, bringing with it the promise of growth that an inland rival could not match. The line still cuts the city in two. To the north lies the Alto, climbing toward the bardas with its boulevards, government buildings, and high-rises. To the south sits the Bajo, the older commercial quarter. Between them spreads the Parque Central, wrapped around a railway station that looks almost comically small for a metropolitan area of more than half a million people. Several of the old railway buildings have become museums now, brick relics of the era when steel track, not shale, decided which towns would live.

For all its modern hustle, Neuquén knows how to slow down at the water's edge. Along the Limay, the Paseo de la Costa threads past river beaches where families gather through the long, hot summer between November and early April. The current runs strong and cold off the mountains, fast enough that lifeguards keep a wary watch and locals warn newcomers away from the deceptively dangerous Neuquén river entirely. Kayakers and canoeists work the channels year-round. In the Río Grande neighborhood there are parks and quiet stretches of shoreline, and on a still evening the water reflects the bardas turning gold, then rose, then violet. It is the kind of light that makes a desert city feel, briefly, like an oasis again.