Jon Durand has dared loop-the-loop aerobatics on the leading edge of the Morning Glory, a rarely spotted, two kilometer-high tube cloud phenomenon.
Adventurers seek new and extreme challenges.
A team of extreme climbers faces the deadly Mount Roraima, the highest of the Tepui plateaus, in Venezuela; when one of their own is met with a serious fall, they find themselves in over their heads.
If Troy Watson and Kieran McKay can connect New Zealand's Nettlebed and Stormy Pot systems, the find will be the biggest cave in the southern hemisphere.
