Blistering heat bakes two nude travelers as they traverse a hellish green landscape. Bare feet trudge through sticky mud mined with jagged rocks and irate wildlife. Swarms of mosquitos gorge on human blood, cutting hundreds of welts into soft, dirt-smeared flesh. As the pair walk and swat futilely at the bugs, they fume, coiled rage barely contained after their most recent argument over a snake egg lunch.

It’s nightmarish for them — but just another day at the office for contestants on Discovery’s hit series “Naked and Afraid,” which is in its seventh season and to date has aired over 70 episodes. The show became an instant sensation when it debuted in 2013, and it’s easy to see why. In each episode, two survivalists, a man and a woman, are placed on a miserable stretch of deeply inhospitable land, where they must survive for 21 days.

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Other than one survival item of their choice and a bag, contestants go in with nothing — not even a stitch of clothing. One wouldn’t be wrong to label this as a gimmick, but it’s successfully gained the show a huge following.

Most viewers will tell you that the shock of the show’s nudity, which is blurred in the front but not the posterior, wears off quickly. What’s more interesting are the brutal, often dangerous conditions these brave and/or crazy adventure seekers face from the moment they arrive at their destination.

Putrid puddles of water might be all there is to quench one’s thirst. Insects, snakes, and other animals that could charitably be termed “exotic” might be harvested for meager protein. Contestants work through sun-scorched deserts, oppressively humid jungles thick with repulsive insects, and various other earthly hellholes most people wouldn’t visit for a hefty paycheck, much less for fun and TV entertainment.

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The contestants don’t even get a prize other than the most coveted of all among survivalists: bragging rights.

The contestants themselves are often picked as yin and yang; a burly veteran could be paired with a hippie flower-child, or a reserved housewife might be partnered with an impatient alpha male.

The show has proven to have surprisingly broad appeal, from amateur survival enthusiasts to those who just want to gawk at the spectacle. A relentless rotation on cable combined with effective storytelling and the outrageous premise have earned the show a spot in the zeitgeist.

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It would be a cliché and not altogether inaccurate to say that the contestants’ biggest challenge is getting along one another, but it’s close. Turns out, it’s stressful being nude with a stranger while you’re hungry, thirsty, and covered in bug bites — and that stress can easily translate into acerbic feuds. On more than a few occasions, one contestant has “tapped out,” leaving his or her partner alone while bitterly blaming that person for the failure.

Lacey Stark-Jones, 31, is one of the show’s triumphant winners. The southern Illinois resident survived 21 days in a hurricane-ravaged Belizean jungle, even making it 10 days after her partner had to tap out due to sickness. Like most of the contestants after the show began, she started off as a viewer.

“I was a huge fan,” Stark-Jones told LifeZette. “Both my children loved the show. My husband loved the show. My daughter is star-struck. She’s so proud of me. She says, ‘I can’t believe you’re on there!'”

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The popularity of “Naked and Afraid” begged for a spinoff, which came in the form of “Naked and Afraid XL,” which debuted in 2015.

On “XL,” the season follows several groups of three contestants in a region as they attempt to survive for 40 days. Whereas a normal “Naked and Afraid” depicts the self-contained, one-show experience of a pair, “XL” spreads it throughout a 10-episode season.

“Going outside is sort of not cool anymore.”

Stark-Jones returned for the current season of “XL,” where she works with two other female contestants to survive in a Brazilian jungle. She says her appearance on the show gives her a goal that goes beyond bragging rights: It encourages others to get engaged in outdoor activities.

“Going outside is sort of not cool anymore. I think ‘Naked and Afraid’ is doing its part in making it cool again, showing people how exciting nature really is,” she said, adding, “I have people coming up to me all the time and telling me how they’re now going camping and taking their kids outside.”

New episodes of “Naked and Afraid” air on Discovery on Sundays at 9 p.m. ET, followed by “Naked and Afraid XL” at 10 p.m ET.