BBC Earth HD

Alaskans power through the dog days of summer.

Michael examines how railways have shaped the world economy. He recalls how the first tracks were laid to shift coal and iron ore, using animals or winches, long before locomotives were invented.

Bettany arrives in the Peloponnese, a peninsula that's home to some of ancient Greece's most legendary kings and vicious warriors.

It's time to celebrate, as Steve Backshall's team of ten shark saviours have all passed their dive training and are now fully qualified scuba divers.

Michael Portillo looks at how railways gave birth to modern tourism, as the first railway companies were quick to spot a business opportunity.

As winter's presence descends upon Alaska, its residents endure battles of wit and nature, learning valuable lessons from both as they progress.

Ben journeys to Ireland's Atlantic coastline in the bleak midwinter. He stays with Judith, an 80-year-old who rejected a modern way of life for one closer to nature.

Bettany arrives in the Peloponnese, a peninsula that's home to some of ancient Greece's most legendary kings and vicious warriors.

The natural world is full of colours. For us, they are a source of beauty, but for animals they are a tool for survival. David Attenborough reveals the extraordinary ways in which animals use colour.

Adventurer Ben Fogle meets Vanessa Forero deep in the Sierra Nevada de Santa Marta, an isolated mountain range in the north of Columbia.

Alaskans power through the dog days of summer.

In Coimbra, there are visits to a convent, a mosque and a synagogue. Finally, after 14 days and 364 kilometres, the group finally reach the famous Sanctuary of Fatima.

Ben Fogle travels to Brazil to meet Chris, a Scotsman who has chosen to make his home in one of the most remote areas of the jungle near the Amazon river.

With winter tightening its grip, Alaskans buckle down and ready themselves for the long months ahead.

Comedian, actor and travel enthusiast Griff Rhys Jones journeys from Brisbane to Cairns aboard the Spirit of Queensland railway.

Comedian and travel enthusiast Griff Rhys Jones continues his journey Down Under. On the Spirit of the Outback, travelling to Queensland's west, Griff seeks to uncover what makes 'the good life'.

Joanna begins with Paris. She takes a hot-air balloon ride, visits the fire-damaged Notre-Dame and meets heiress Daphne Guinness.

Joanna continues her travels to Rome, a city like no other on earth. She zips into the city on the back of a Vespa to get her first glimpse of the beauty that awaits.

Joanna continues her travels to Berlin. A sometimes dark history has given birth to a creative city with a thrilling atmosphere.

Gregg Wallace visits a factory with a menthol scent. The Polos factory in York produces 32 million every single day. They have been churning out these little holey wonders since 1948.

Dr Michael Mosley and the 30 other patients enrolled in the trial are diagnosed with chronic, but common sleep disorders.

On Great Blasket Island, off the coast of Ireland, Ben stays with London couple Dan and Emily, who landed an extraordinary job as island caretakers on Europe's rugged western frontier.

As the sun fades across the land, Alaskans brace for Dark Winter's return.

Michael Portillo explores how railways have contributed to the creation of countries, linking people across deserts and mountains and binding together different ethnicities and religions.

Bettany sails through the Corinth Canal, and from Corfu she ends her journey at Ithaca.

Michael explores how railways enabled the dissemination of cultural, social, religious and political ideas, and celebrates the cultures which his antique Bradshaw's railway guidebook has introduced him to.

In Varanasi, Bettany takes part in a Hindu ritual which helps her process her own bereavement. She also takes a boat out to the Lake Palace on an island in Lake Pichola.