La Cumbre is the top of the world for most riders, a cold, windy pass at about 4,650 metres on the edge of the Altiplano, where the road from La Paz crests the mountains and begins a descent of more than three thousand metres to the tropical Yungas. The name simply means the summit. There is a small shrine, a few stalls and, on a clear day, a view of snow-capped peaks, including Huayna Potosi, glowing white to the north. La Paz, with over 800,000 people in its metropolitan area, lies behind you, and Coroico, a small town in the cloud forest, is far below at the bottom of the descent.
The air is thin at this altitude, and both bike and rider feel it. Engines lose power, and a rider may get a headache, so take things slowly, drink water and avoid exertion. Fuel is not sold at the summit, so fill up in La Paz or El Alto, though be aware that Bolivian fuel prices and rules for foreigners have shifted over the years. The weather is changeable, with biting cold, sudden hail and thick fog. A good jacket and gloves are essential, even at midday.
From the summit, the modern road drops quickly through rocky gorges and into dense green forest, with sweeping bends and good tarmac, while the older road, the infamous Yungas Road, branches off to the north. Nicknamed the Road of Death, it was declared the world's most dangerous road by the Inter-American Development Bank in 1995 because of the number of accidents, and it is a narrow, unpaved shelf cut into a cliff, with drops of hundreds of metres. Since a new road opened, traffic has fallen, and the old road is mostly used by mountain bikers and adventurous riders. Treat it with respect, and avoid it in wet or foggy weather.
The history of the area is rich. The Altiplano was home to the Tiwanaku civilisation long before the Incas, and the Aymara people who live here today speak a language that predates Spanish by centuries. The road itself was originally built in the 1930s, partly by Paraguayan prisoners captured in the Chaco War, which adds a sober note to the ride. Llamas and alpacas graze on the plateau, and condors sometimes soar overhead.
The descent changes the climate dramatically. Within an hour the dry, cold air gives way to warm, wet cloud forest, orchids and bromeliads, coffee and coca terraces, and waterfalls across the road. Pack layers you can add and remove, and keep a rain jacket handy.