Sajama is Bolivia's highest mountain, a near-perfect snow-capped cone that stands alone above a bare, straw-yellow plain at 4,200 metres. The 6,542-metre volcano has stood quiet so long that its slopes have weathered into an almost geometric peak, and its isolation on the flat altiplano makes it look taller still. Its lower slopes hold something no other mountain can claim: groves of queñua (Polylepis tarapacana), gnarled, copper-barked trees that climb to 5,200 metres and form the highest woodland on Earth. Protecting these trees was the reason Bolivia drew its first national park boundaries here in 1939, making Sajama the country's oldest protected area. This is no empty wilderness, though — Aymara herders have lived in its stone-walled villages for centuries, grazing llamas and alpacas in the mountain's shadow and raising tall funerary towers, called chullpas, across the plain.
Most days here begin with steam. At dawn, geyser fields hiss and bubble along cracks in the plateau, and a short walk away you can lower yourself into natural hot springs that hold around 40°C, soaking while looking straight up at Sajama's snowy summit. The high desert is far from lifeless. Vicuña graze the tussock grass, flamingos gather on shallow lakes, and small adobe churches stand in villages that still keep the old festivals; step inside one and the plain exterior turns out to be hiding something. The mountain itself remains a serious climb, glaciated and thin-aired, one of the Andes' great 6,000-metre objectives, though most visitors are content to walk the plateau beneath it. Etched into that plateau are the Sajama Lines, thousands of dead-straight paths scraped into the ground over three thousand years.