It was a sunny, crisp winter's day in Interlaken, Switzerland, and Florida couple Chris and Gail Gursky, married for 26 years and parents to a grown-up son, had the perfect plan to get their hearts pumping - hang-gliding over the gorgeous terrain. They loved zip-lining. Now, it was time to up the ante. And they were keen to get started - it was their first day on holidays.

The instructor strapped Chris in, then they ran off the edge of the cliff together. But as soon as Chris' feet left the ground, his body sank straight down and he knew something was terribly wrong. Horrifyingly, his harness hadn't been strapped on properly. He wasn't attached. And he was hurtling well above the trees. This is how Chris survived...

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