Mountain biking requires endurance, core strength and balance, bike handling skills, and self-reliance. Advanced riders pursue both steep technical descents and high incline climbs. In the case of freeriding, down hilling, and dirt jumping, aerial manoeuvres are performed off both natural features and specially constructed jumps and ramps. Follows several individuals breaking out of their mundane lives and entering into the adventurous thrill-seeking world of this sport.

A look at the very real impact the Back to the Future movies have had on our culture. What was once a little idea that spawned a tightly-focused documentary has grown into something truly amazing over two years of filming. Back in Time is a cinematic monument to the vastness of the trilogy's fandom. In addition to the footage and interviews revolving around the time machine itself, the crew found that simply by delving into the impact of the trilogy an epic journey began to unfold before them. The crew captured countless hours of footage during filming. From Steven Spielberg to Robert Zemeckis and Bob Gale, to the Sheas and Hollers, and from James Tolkan and Lea Thompson to Christopher Lloyd and Michael J. Fox, Back in Time features interview after interview that simply must be seen.

In the annals of Hollywood film since the artistic glories of the New Hollywood era, few have a better reputation and body of work in the field of suspense films exploring the contemporary darkness in American life than Brian De Palma. Here, the great film writer and director takes, us in his own words, through his professional life and a career that redefined film horror and suspense. All the while, he also confesses the challenges of working in Hollywood and the price even the great artists pay for being a part of it.

Narrated by Ewan McGregor, Humpback Whales is an extraordinary journey into the mysterious world of one of nature's most awe-inspiring marine mammals. Set in the spectacular waters of Alaska, Hawaii and the remote islands of Tonga, this ocean adventure offers audiences an up-close look at how these whales communicate, sing, feed, play and take care of their young. Humpbacks were nearly driven to extinction 50 years ago, but today are making a slow but remarkable recovery. Join a team of researchers as they unlock the secrets of the humpback and find out why humpbacks are the most acrobatic of all whales, why they sing their haunting songs, and why these intelligent 55-foot, 50-ton animals migrate up to 10,000 miles round-trip every year.

The contests between predators and prey are the most dramatic events in nature. Taking an intimate and detailed look at the remarkable strategies employed by hunters to catch their prey and the hunted to escape. Sir David Attenborough narrates. "The Hardest Challenge" reveals the extraordinary range of techniques predators use to catch their prey - from a leopard using all its powers of stealth to stalk impala in broad daylight to wild dogs, whose tactic is to wear down their prey over long distances; from Nile crocodiles, the planet's most patient predators, to killer whales who use teamwork and intelligence to take on humpback whales. But even with these finely tuned strategies, the outcome is far from certain. Surprisingly, most predators fail most of the time.

The second episode looks at the challenges of hunting in the Arctic, the most seasonal place on Earth. To a predator, seasonal change is a problem. It means that all the parameters of the hunt - the conditions, the strategies, the prey - change too. The only option for the Arctic's top predators, the wolf, the Arctic fox and the polar bear, is to continually adapt to their changing world, exploiting the good times and enduring the bad.