National Geographic Explorer and author Sarah Marquis has evaded harassing horsemen in Mongolia’s steppes. She spent three days in the Laos jungle with one leg tied to a tree to keep her from falling into water while suffering a fever. But perhaps her biggest challenge on her journeys is finding enough food every day.

That’s because Marquis is an extreme global trekker. For more than 20 years, the Swiss woman has dedicated her life to walking alone for months at a time and lives almost exclusively off the land while she’s doing it. Plus, she’s a vegetarian, which makes places like meat-centric Mongolia particularly difficult to navigate. (Finding buckwheat in the desert there made her day, she says.)

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