Steve Backshall leads a team of elite explorers - including world leading underwater cave explorer Robbie Schmittner, former Royal Marine Aldo Kane and diving camera operator Katy Fraser - into the wilds of the Yucatan Peninsula in Mexico. Under the vast jungle here is the largest unexplored network of caves in the world, comprising thousands of kilometres of passageways. They are stunningly beautiful but incredibly dangerous - much of the system is under water. First the team must trek through tough, scorpion-infested jungle to camp alongside a giant sinkhole in the jungle floor - a dark gateway to an underworld full of nightmarish creatures.
In a revelatory look at Svalbard, the most northerly region in the series, Steve Backshall leaves no stone unturned as he unravels the secrets that lie covered in ice for most of each year. Svalbard is cold, dark and foreboding, yet it is home to the world's largest land predator and the most northerly population of large herbivore, but Steve discovers that the real secret to this place comes from a very different world.
This episode focuses on the Jurassic period, a time when the first giant killers stalked the Earth and lurked in the seas; a time when the slightest advantage meant the difference between life and death. In North America the iconic allosaurus, an ambush hunter with a lethal bite, dominated. Not even the heavily-armoured stegosaurus was safe from this killer, and incredible evidence reveals a glimpse of a vicious battle between these two giants. Life in Jurassic oceans was no easier; in 2008, a fossil was dug out of a frozen island high in the Arctic. It was a colossal marine reptile, twice as big as most ocean predators, at 15 metres long and weighing about 45 tonnes. This was Predator X. Its skull alone was nearly twice the size of a tyrannosaurus rex's, and its bite force unmatched by anything in the Jurassic seas. The balance of power between predator and prey is a fine one, as prey continually evolves different ways to avoid predators. But for the most successful and enduring predators, the battle to survive has always been tipped in their favour.
For a river that conjures up images of pyramids and pharaohs, the Nile turns out to be a truly surprising river that changes at every twist and turn of its journey. As its flows into increasingly arid latitudes on its journey north it becomes an evermore vital lifeline for animals and people, but only if they can conquer the challenges that this ever-changing river throws at them.
The Cretaceous was the golden age on ancient Earth. Magnificent and terrifying dinosaurs like Triceratops and Tyrannosaurus ruled the land. But they were all wiped out in an instant by one of the most powerful impacts our Earth has ever endured -- a collision with an asteroid!