Chimborazo

Chimborazo was built in three parts, one after another.

Long ago, part of it fell down in a huge landslide.

IG-EPN explains that Chimborazo is made of three volcanoes built one after another. The oldest, the Basal building, was active between about 120,000 and 60,000 years ago. Then a huge part of it collapsed, and an avalanche of rock spread over the plain where the city of Riobamba stands today.

A second building grew from about 60,000 to 35,000 years ago. Then activity moved west and built the youngest part, whose summit, called Whymper, is the highest.

IG-EPN: three successive edifices. The mainly effusive Basal edifice (about 120-60 ka) ended with a dome complex and was cut by a large sector collapse 60-65 ka; the debris avalanche covers about 280 km2 of the Riobamba plain, averaging 40 m thick, with an estimated 10-13 km3 in volume.

The Intermediate edifice grew in the collapse scar's eastern part from 60 to 35 ka (its remnants are the Politécnica and Martínez summits); activity then migrated west to build the youngest edifice, whose Whymper summit is the highest. The average eruptive rate, about 0.8 km3 per thousand years, has decreased to about 0.1 km3 per thousand years for the youngest edifice.

The Earth is a little fatter around its middle. Chimborazo is near the middle.

So its top sticks out farther into space than any other place.

Mount Everest is the highest mountain above sea level. But NOAA explains that the Earth is not a perfect ball: it is a bit thicker at the Equator because it spins.

Chimborazo is just one degree south of the Equator, where this bulge is greatest. So its summit is more than 2,072 meters farther from the center of the Earth than the top of Everest. NOAA says that makes Chimborazo the closest point on Earth to the stars.

NOAA's National Ocean Service: Everest (8,848 m) is the highest point above global mean sea level, but Earth is slightly thicker at the Equator because of the centrifugal force of its rotation. Chimborazo, one degree south of the Equator where the bulge is greatest, therefore has the highest summit above Earth's center: although it is 6,268 m above sea level, it is over 2,072 m farther from the center than Everest's peak.

The National Geodetic Survey makes such comparisons by mapping Earth's gravity field and fixing the precise positions of points on its surface.

Wild vicuñas live on the grassy slopes. They are cousins of llamas.

Condors and hummingbirds fly here too.

The land around the volcano is the Chimborazo Fauna Production Reserve, created in 1987 to protect the cold grasslands called páramo and the camel relatives of the Andes: the vicuña, the llama and the alpaca. Ecuador's submission to UNESCO says vicuñas were brought back after they had disappeared from the area.

Andean condors, white-tailed deer, foxes and the Chimborazo hummingbird live here too. The volcano's glaciers feed rivers and water systems that thousands of people use.

Ecuador's 2026 Tentative List entry: the Chimborazo Fauna Production Reserve (1987) conserves páramo and puna ecosystems and native camelids (vicuña, llama, alpaca); glaciers, moors, wetlands and high puna host the Andean condor (Vultur gryphus), the vicuña (Vicugna vicugna), reintroduced after its local extinction, and the Chimborazo hummingbird (Oreotrochilus chimborazo), with white-tailed deer, foxes and moorland rabbits.

The glaciers feed watersheds and irrigation systems that supply water for drinking, farming and livestock to thousands of people in several central provinces.

The air is very thin up high. Go up slowly and rest.

Tell a grown-up if your head hurts.

Chimborazo's high slopes have very thin air. The CDC says going up slowly gives the body time to adjust, and that children can get altitude sickness just like adults. A headache is the main sign, and going down at least 300 meters helps people feel better quickly.

IG-EPN watches the volcano for earthquakes, ground movement and changes in its hot springs, because it is considered potentially active.

CDC Yellow Book: ascend gradually (above 3,000 m, raise sleeping altitude by no more than 500 m a night); children are as susceptible as adults; headache is the cardinal symptom of acute mountain sickness, which improves rapidly with a descent of 300 m or more.

IG-EPN considers Chimborazo potentially active (average interval between eruptions about 1,000 years) and monitors seismicity, deformation and hot springs; it notes that the glacier cap, steep flanks and nearby towns raise the potential risk.