
Adventurers seek new and extreme challenges.

Onekotan is a Pacific island with a collapsed volcano that Matthias Haunholder wants to ski down.

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.

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.

Stefan Glowacz and Chris Sharma descend into Majlis al Jinn in Oman, the second largest known cave chamber on the planet, located about 1500 metres above sea level.