Paso Sico is a border crossing between Argentina and Chile that lies at over 4,000 metres in the middle of the Altiplano, and it is more of an idea than a place. There are no villages, no shops, only a gravel road crossing a high, dry, wind-blasted plateau, with salt flats, volcanoes and small lakes that flash silver or pink in the sun. The route runs from the Argentine province of Salta to San Pedro de Atacama, in Chile, crossing a landscape that most people never see, and the sense of emptiness is overwhelming.
The scenery is immense. Salt pans lie in pale, flat expanses, with flamingos in shallow pools and vicuñas pacing across the dry grass. Volcanoes rise on all sides, many of them over five thousand metres, among them Socompa, on the border, whose eruption long ago left a vast landslide field. On the Chilean side, the road passes lakes such as Miscanti and Miñiques, which are a deep blue, set against reddish mountains, and the contrast is spectacular. The air is clear and thin, and the stars at night are astonishing.
This is not a road for the casual rider. The surface is mostly gravel and sand, with washboard, rocky patches and the occasional river crossing, and the weather can change sharply, with strong wind, snow and freezing temperatures even in summer. Altitude brings its own problems: engines lose power, and riders can suffer from headaches and fatigue, so acclimatise before you go. The border post may keep restricted hours or close in bad conditions, so check ahead and carry your paperwork. You must be self-reliant.
Fuel is the main practical issue. There are no pumps at the pass or anywhere near it, so carry enough fuel for the whole crossing and a margin, and plan your supplies in the nearest towns on each side. Calama, on the Chilean side, has large fuel stations and shops. Bring water, food and warm clothing, a repair kit, and a satellite communicator if you have one. Ride with at least one other vehicle and tell someone your route. If you do it right, you will remember the silence for years.