The Sierra de la Ventana is a surprise in the middle of the pampas. After hundreds of kilometres of flat grassland, cattle and wind, the horizon in the south-west of Buenos Aires province lifts into a chain of folded quartzite ridges, the Sierras Australes, that rise to just over a thousand metres, grey and bare on top, and green with streams and groves of poplar below. The range is named for a natural window, the ventana, a gap in the crest of Cerro de la Ventana that frames the sky, and a steep path up the mountain leads to it for those who like walking.
Charles Darwin passed through in 1833 on his long journey across the pampas, and climbed to the ridge, and the account of his ascent is a point of local pride. In the valleys, the small town and nearby Villa Ventana grew up as a resort in the early twentieth century, when railway travel brought Buenos Aires families, and the style is that of a weekend retreat: stone and timber cottages, shady avenues, small guesthouses, a river for swimming and tea rooms with cakes. Most visitors come for the quiet, for walking and for the asado, the long Argentine barbecue.
A night here is a good way to break a long ride south-west from the capital. The roads leading in cross open grassland with huge skies, and wind is the main force, sometimes strong enough to push a bike sideways, so keep both hands on the bars and ride steadily. The approach roads are long and straight, but within the hills the lanes wind gently along streams, with tight bends and unpaved sections on some of the side roads. Watch for cattle on the road and for trucks on the main route.
Fuel is the thing to plan. The village has a station, but supplies can run out, so fill up when you can in Tornquist or Saldungaray on the way. Weather is variable, with cool nights even in summer, and snow possible on the highest ridges in winter. The best seasons are spring and autumn, when the days are mild and the hills green or golden.