Watch Natures Most Amazing Events online: Episode 2 Grizzly Wilderness

The return of the Pacific salmon every year to the rivers from which they were born is one of the greatest natural events on the planet. More than half a billion salmon travel up to 20,000 miles to return to the exact patch of gravel in the river from which they were born, to spawn and die. Nature's Most Amazing Events travel to the west coast of Canada and Alaska to capture the salmon's return, along with the predators who eagerly await their plentiful prey. In a TV first, the team films the emergence of a mother grizzly and her cubs from their dens high in the snowy Alaskan mountains. Using a gyro-stabilized aerial camera system, they are able to follow them down a near vertical slope as they make their way to the coast where the fresh new plant life first appears in the spring. Using high speed cameras and a specially designed digital underwater kit, the team is able to record how the salmon swim upstream against powerful torrents. Filming at 100 times normal speed, they reveal how the salmon are able to leap over waterfalls equivalent to a human jumping over a four storey building. But despite their monumental struggles, the salmon face a greater challenge up river ? dozens of hungry bears. Slow motion shots of the bears reveal their hunting techniques, while the underwater cameras record another TV first to show how they use their ingenuity and some fancy footwork to collect dead salmon from the bottom of deep pools. Tune in for these amazing moments of nature and more, all caught on camera with the latest cutting-edge technology.

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