Sol de Mañana is a field of steaming holes in the ground at nearly five thousand metres, on the high desert of south-west Bolivia, and arriving there feels like landing on a small, hostile planet. Fumaroles hiss from the cracked, yellow-stained earth, mud pots bubble and plop, and a smell of sulphur hangs in the cold air. At dawn, when the temperature is below freezing and the steam is at its thickest, the whole field looks as if it were on fire, and the sun comes up behind it in ribbons of orange.
The geothermal field lies in the Eduardo Avaroa National Reserve, a vast area of salt lakes, volcanoes and desert on the Bolivian altiplano close to the Chilean border. This is some of the most remote country in South America, with flamingos on Laguna Colorada, a lake stained red by algae and minerals, and, further south, the green and white shores of Laguna Verde under the cone of Licancabur. The reserve charges an entrance fee, and the tracks are mostly unsurfaced, sandy or gravelled and often corrugated, with soft patches that can swallow a loaded motorcycle.
Riding here is serious expedition travel. The distances between services are huge, the altitude is brutal, and there is almost no help if something goes wrong. Altitude sickness is a danger and breathing is hard, so take time to acclimatise in Uyuni or elsewhere first. Engines run poorly in thin air, nights are bitterly cold, and the wind arrives in the afternoon, driving sand across the plain. Many riders go with a support vehicle or with a local guide, which is sensible, and most visitors arrive by jeep from Uyuni on a three-day trip that crosses the salt flat.
At the field itself, stay well away from the edges of the pools and the thin ground between them. The crust is fragile, the mud is hot enough to scald badly, and people have died by stepping where they should not. Stay on the paths, keep your distance from the steam vents, and do not let children wander. The ground can look solid and be a thin skin over boiling mud.
There are no services at the geysers. Carry extra fuel, water, food, warm clothing and tools, and tell someone your route. Shortly after dawn is the best time, when the steam is at its peak and the light is soft, and it is also the coldest, so bring gloves that you can really trust.