BBC Earth HD

'S4/E3'. Arriving in Skagway by seaplane from railway-less Juneau, Michael Portillo heads for Dyea and the Chilkoot trail, which the first gold prospectors hiked 100 years ago to the Klondike.

'S4/E4'. Michael Portillo explores British Columbia. He discovers how two superpowers nearly came to war over a pig and joins the Royal Canadian Navy to firefight on board the frigate HMCS Regina.

'S1/E1 - The Hardest Challenge'. This series looks at the relationship between predators and their prey, including how leopards use stealth, wild dogs use stamina and killer whales use teamwork and intelligence.

'S1/E2 - In the Grip of the Seasons'. 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.

'S1/E3 - Hide And Seek'. Hide and Seek follows tigers, harpy eagles, chimpanzees, army ants and other predators as they rise to the challenge of hunting within the forest - a dense, confusing, three-dimensional world.

'S4/E3 - New Zealand'. A stunning rail journey through the heart of New Zealand's best scenery starts in Greymouth. Taking in Arthur's Pass National Park, Cass and on to the Waimakiriri gorge before ending at Christchurch.

'S4/E4 - Norway'. In this episode we travel from Bergen to Oslo, on a super-fast train.

'S4/E5 - Southern Australia'. A coast-to-coast journey through the Australian outback along the iconic Indian Pacific Railway. It takes two days to travel from Sydney to Adelaide.

'S4/E6 - Far North Scotland'. We travel the Far North Line between Inverness and Wick, a four-hour ride that travels along the coast, and has Dunrobin Castle as one of its sights along the way.

'S2/E1'. Travelling to Arran and Holy Isle, Ben Fogle learns how they're a haven for diverse faiths and beliefs, makes Jewish challah bread and visits a Buddhist peace centre.

'S2/E2'. Ben Fogle journeys to Islay and Jura, tracing the route of 6th-century Christian monks across wild seaways to discover communities going the extra mile to look out for one another.

'S2/E3'. Ben Fogle heads for the Orkney Isles to investigate Norse Christian heritage and how they are a place of modern pilgrimage, offering a place of deep time and space to reconnect.

'S1/E4 - The Dolphin'. How did the dolphin get so smart? Chris Packham explores the origins of senses, brains and intelligence, in an evolutionary odyssey that ventures from ocean to land and back again.

'S1/E2'. As the Wildcard prepare for their first unload of the season, Prue and three-year-old daughter Ellica find themselves out at sea and face-to-face with a hungry shark.

'S1/E1 - Hoi An'. Landing at Hoi An, Bill Bailey finds himself in a basket-shaped boat facing the seas of change that have shaped the country since the end of the Vietnam War.

'S1/E1 - Episode 1'. Following the largest fish in the world on a year-long voyage to find out where they disappear to after feeding en masse on Australia's Ningaloo Reef.

'S1/E3'. Alice digs into stories behind Rome's world-famous ancient landmarks and the Roman empire's debt to the Etruscans. Then in Florence, it's time for cocktails.

'S2/E3'. Ben Fogle heads for the Orkney Isles to investigate Norse Christian heritage and how they are a place of modern pilgrimage, offering a place of deep time and space to reconnect.

'S1/E2'. As the Wildcard prepare for their first unload of the season, Prue and three-year-old daughter Ellica find themselves out at sea and face-to-face with a hungry shark.