To prepare for a dark and cold winter, Alaskans harvest necessary resources.
Alaskans race to secure resources and ready their camps for the coming dark winter.
How the cameramen filmed underwater.
Mating of the Vogelkop bowerbirds.
In the midst of dark winter, Alaskans burn the midnight oil to complete necessary tasks.
Alaskans scurry to find precious resources in a constantly changing winter landscape.
At the apex of winter, a lack of snowfall in the Arctic makes basic tasks more difficult.
Alaskans learn new survival skills as winter loses its grip on the Arctic landscape.
In the final days of winter, Alaskans use their time to prepare for what lies ahead.
The arrival of longer days and warmer temperatures makes for easier travel, and Alaskans take advantage by heading out to hunt migrating birds and harvest meat and fur, securing their camps to protect them from flooding in the meantime.
A record-breaking twister rips through Alabama. In South Africa, a violent storm with near-hurricane winds breaks the mooring lines of super-tankers. In Maui, a young daredevil is caught in a flash flood and swept off a massive waterfall.
Hurricane Harvey, one of the most powerful hurricanes to strike the United States, rips a coastal town apart and dumps a once-in-a-thousand-years rainfall that drowns the city of Houston.
Two devastating earthquakes hit Mexico in quick succession. An Australian storm-chaser becomes trapped in the middle of the most powerful tornado ever recorded in El Reno, Oklahoma.
A rare tornado decimates a small town in rural Uruguay, snaring a man in his car and obliterating a huge warehouse. Meanwhile a thrill seeker fulfils his ambition to reach the world's largest lava lake.
Vehicles flee an enormous tornado as it crosses a highway outside El Reno, Oklahoma. A big wave surfer narrowly escapes death and a dust storm interrupts a wedding in Phoenix, Arizona.
A man is almost crushed by his own house in a freak winter tornado in Illinois. Meanwhile, a falling glacier in Greenland unleashes a tsunami-like wave onto watching tourists.
Steve ger sig ut i kajak bland isflaken i Arktis och blir jagad av både isbjörn och valrossar, som väger nära två ton. Teamet bockar av ännu några farliga bestar innan de lämnar Svalbard för Somerset Island i norra Kanada.
Tourists in Thailand are totally unprepared when a tsunami crashes into 14 countries in the Indian Ocean, killing 250,000 people on Boxing Day 2004.
To capture footage of the volcano's molten heart, the aerial team must deal with ferocious winds and clouds of volcanic gas: this is aerial filming at its most extreme. Meanwhile, the cave team is dropped close to the summit.
The Japanese tsunami sees entire towns washed away and people trying to outrun the wave in the country's biggest national disaster since the Second World War.
As Hurricane Matthew pounds six countries, Haiti is devastated by it. A honeymooning couple are trapped. Police try to rescue drowning car drivers.
Vad kan klyva berg och bilda nya isflak? Teamet har begett sig till Alaska på jakt efter fler farliga djur, men hamnar först inför en av jordens mest skräckinjagande naturkrafter. Här får de också en nära titt på det största landrovdjuret, grizzlybjörnen. De får även en rejäl uppvisning av ett gäng knölvalar som kan väga upp till 40 ton.
Hard lessons must be learned in order to survive during the dark winter in the Arctic.
Alaskans attempt to survive whilst struggling with unpredictable winter weather. Jessie prepares for the Iditarod and Sue Aikens braves freezing conditions to make a bed.
Naomi relives her travels and adventures from the safety of the sofa. She decides which animal has received the best nightmare makeover and crowns an encounter as her ultimate nightmare.