Ice climber, Will Gadd, pushes the boundaries of the sport by climbing the frozen 140m-high cave behind Helmcken Falls, BC, Canada. He faces freezing temperatures, exhaustion, and an ever-changing landscape.

The Inga Rapids of the Congo River are the holy grail of kayaking, with bigger and more dangerous waters than anywhere else on earth. Steve Fisher and his team set out be the first to run this 50-mile, churning behemoth of white water.

Attempting the first ascent on the face of Mount Roraima, located deep in the jungles of Guyana, is an insatiable draw for climbing legend Stefan Glowacz and his team. But a tragic accident changes the drive to conquer this massive, majestic, mesa.

Majlis al Jinn, a huge subterranean chamber in Oman, is big enough to house the Great Pyramid of Giza. Climbers Chris Sharma and Stefan Glowacz attempt an ascent from the bottom of the cave, up the massive arch, back to the light of the surface.

Rafa Ortiz and a group of kayakers who specialise in big waterfall drops attempt to run a section of the Mexican Rio Santo Domingo that is the steepest navigable whitewater on Earth. It's a feat that nearly killed Rafa just four years prior.

Zeb Walsh has dreamed of paddleboarding the channel between Australia and Tasmania since he was 15 years old. In his death-defying attempt, he enlists two friends to brave the choppy, shark-infested waters of the Bass Strait and make history.

Combining the fastest elements of both skiing and paragliding, speed riding is one of the most exciting winter sports in the world. Jon Devore and some of the most accomplished athletes in the sport want to tackle the 'unrideable' giants of Alaska.

The Bahamas are home to some of the world‘s most stunning and extensive underwater cave systems. Diving legend Brian Kakuk believes that two of the biggest systems there are actually one massive one and he is determined to prove it.

Antarctica's Mount Erebus, the most southern active volcano, has one of only five permanent lava lakes in the world. British geologist Clive Oppenheimer sets out to measure the temperature of the volcano’s lava, but faces random eruptions as he does.