Las Leñas is Argentina's premier ski area: go there for the best and most extensive off-piste terrain in the southern hemisphere. It is a small, unpretentious, purpose-built resort with pyramid-style architecture beloved by the French in the 1960s. There are a couple of smart hotels, a few bars and a casino served by village bus. It's a remarkable place miles from civilisation, 400km from the nearest major airport at Mendoza and set in a vast mountain wilderness. The slopes offer a small area of groomed pistes, suitable for all levels, but the main attraction is for experts. An old double chair opens up a lot of ski-anywhere, steep off-piste terrain - which you can only enter once you sign away the resort's responsibility for you. And it is best explored with a guide. There is good cat skiing too. Be warned though: gales and blizzards can shut the lifts for days. Late season is the best time to visit, and it's worthwhile considering combining the trip with Chilean resorts.