Wingsuit flight videos have a way of making viewers' palms sweat. Add the danger of zipping through a narrow cave and your hands will feel like a Florida swamp.
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Fearless BASE jumper Alexander Polli took off on his death-defying flight in the Roca Foradada Mountains of Montserrat, Spain. Polli reached speeds of 155 mph (250 km/h) before cruising through an opening no larger than six feet across. The terrifying experience was captured in HD on multiple cameras -- including one on Polli's helmet -- to create a viewing experience with maximum impact.
Grab a towel for your hands and push play.
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