Inside Kenya’s Rift Valley, which produces the world's best marathon runners year after year

A group of runners takes part in a training session on March 12, 2019 in Kaptagat. Franck Fife / AFP / Getty

Kenya is home to many of the best marathon runners in the world.
It's no coincidence. Many of these world-class runners come from Iten, the "city of champions," a town that sits on the edge of Rift Valley, 7,000 feet above sea level.
Scientists and runners have questioned how they keep winning.
Harvard biologist Daniel Lieberman, who studied the evolution of running, told NPR it was impossible to quantify — it's a mixture of factors like training, culture, biology, and the runner's determination.
What used to be an unknown region is now a mecca for runners from around the world due its repeated successes.
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Kenya's Rift Valley is a mecca for running champions.

For decades runners from Kenya and Ethiopia have been dominating distance races. From 1968 onwards, Kenyan athletes have been a force to reckon with.

And what's intrigued runners and experts is that so many champions come from, or train at, Rift Valley in Kenya. In particular, the town of Iten, which sits on the edge of the valley 7,000 feet above sea level, has produced so many marathon runners that it's known as "the city of champions."

But there's no clear factor for the region's repeated successes. It's a variety of things like altitude, training, culture, and runners' determination.

One thing's for sure — from an early age, local children watch runners crowd the streets and dream of following in their footsteps. A successful career as a distance runner is a way out of poverty.

Here's what Rift Valley is like.