The coast is the dynamic border between land and sea; powered by the tides and thrashed by waves, this is a world of continuous change. Opportunities never last long here, so hunters are always in a race against time. The coast is the only place on the planet where predators from air, land and sea come together. Dolphins that leave the safety of the sea to fish, walking octopuses, ingenious monkeys, fishing wolves and the greatest gathering of feeding humpback whales come to the coast to hunt. For all, timing is everything.

In the fourth episode of the series, legendary nature and cultural photographer Art Wolfe captures the great brown bear with the stunning backdrop of Alaska’s mountains and glaciers, immigrating wildebeests in the plains East Africa, and the hard-to-find gorillas of Uganda.

Grasslands cover one quarter of all land and support the vast gatherings of wildlife, but to survive here animals must endure the most hostile seasonal changes on the planet. From Asia's bizarre-looking Saiga antelope to the giant anteaters of Brazil, grassland animals have adapted in extraordinary ways to cope with these extremes. In the flooded Okavango, lions take on formidable buffalo in epic battles, on the savannah bee-eaters take advantage of elephants to help catch insects and, on the freezing northern tundra, caribou embark on great migrations shadowed by hungry Arctic wolves.

Every year grizzly bear families in North America depend for their survival on a spectacular natural event: the return of hundreds of millions of salmon from the Pacific Ocean to the mountain streams where they were born. The salmon travel thousands of miles to spawn and then die. The great run not only provides food for bears, but for killer whales, wolves, bald eagles, and even the forest itself. The question is: will the salmon return in time to keep hungry bears alive?
A mother grizzly and her cubs emerge from their den high in snowy Alaskan mountains. Filming from the air the team capture a TV first, following the bears as they negotiate a near vertical slope on their journey to the coast where they await the return of the salmon. Meanwhile, the salmon are making their way to the to river mouths where they must swim upstream and against the current. The programme reveals how they tackle the torrents and leap over waterfalls, a feat equivalent to a human jumping over a house. Dozens of hungry bears eagerly await the salmon that make it up river. In another TV first, underwater cameras record the ingenuity and fancy footwork they use to collect dead salmon from the bottom of deep pools.

Tom Service plunges into the life and times of Mozart to try and rediscover the greatness and humanity of the living man in his moment. Mozart's prodigious output and untimely death have helped place him on a pedestal that can often blind us to the unique brilliance of his work in the context of his life and times. Service visits the key cities and rooms in which Mozart lived and worked, plays some of Mozart's original instruments and scores, and gradually uncovers the brilliance and originality of his work." There is the prodigious childhood when Mozart was feted as an infant phenomenon around Europe's most glittering courts, and his golden decade in Vienna in which masterpiece followed masterpiece - operas, symphonies, piano concertos, string quartets - as if this short, high-voiced man-child must have been taking dictation from some divine source, until his death at the age of just 35 in 1791. Even more than the music, Mozart's tragic demise sets the seal on his myth. The trajectory of Mozart's life sets the template for the romantic paradigm whose throes we are still in today, which requires our creative heroes to die young to prove that they were too good for this madding world, whether it be Wolfgang Amadeus or Jimi Hendrix. Service travels from London to Vienna and Salzberg, unpicking the living, breathing genius that was Mozart. With Sir John Eliot Gardiner, Nicola Benedetti, Paul Morley and others.

Silk is the invertebrates' great invention, used in a range of ways from from the protective stalks of lacewing eggs to the amazing hanging threads of New Zealand's 'glow worms'. Spiders, though, have taken silk-spinning to extremes. The common wolf spider has no web, but the female is a gentle parent, encasing her eggs in silk and carrying the precious bundle wherever she goes. The bolas spider uses a ball of sticky silk soaked in a copy of moth pheromone to lure its prey. Millions of communal spiders live and feed together in a vast, towering web - an arachnophobe's nightmare.