Steve travels to Guyana and is the first person ever to look for creatures at the bottom of a roaring waterfall. To get there he must abseil down 240 metres of rope into the roaring unknown around the plunge pool. It is a paradise for frogs and, even though he is hundreds of miles from the ocean, it's a haven for crabs. But Steve also discovers that it is no place for humans. Drenched by freezing spray, we leave him sheltering under a flimsy tarpaulin in the middle of an electrical storm.

Steve continues his search for undiscovered animals in South America, joining a group of scientists, naturalists and film-makers all united by the common goal of saving Guyana's wildlife. They will record every animal they see in the hope of proving these jungles are too precious to be cut down. Steve ventures up unexplored rivers discovering that real-life monsters lurk in the deep... including caimen, sabre-toothed hunters, blood-sucking parasites and a fish totally new to science.

Steve ventures into Venezuela to undertake one of the deadliest adventures he'll ever face. His mission is to climb a totally unexplored mountain to find out what animals live at the summit. Isolated for millions of years, the top promises to be a lost world inhabited by creatures totally new to science. Steve sleeps the night in a glorified camp bed strapped to the rockface - above him 200 metres of loose rock and below him 200 metres of nothing. They make great progress towards the top, but then Steve loses his grip and falls from the rock, where he is left dangling in thin air 250 metres above solid ground.

Steve continues his adventures in Venezuela to reach the summit of a totally unexplored mountain. Back on the rock after his fall, the team climb right into a mysterious cave which contains the bones of unknown animals. After one more night on the cliff face Steve eventually becomes the first person ever to reach the summit. He finds a lost world with frogs never seen by science and undertakes an epic night of moth, bug and bird surveys culminating in the discovery of a new species of mammal.

Steve Backshall travels into the heartland of Papua New Guinea, a lost world covered in thick jungle and teeming with strange wildlife found nowhere else on earth. Working with an international team of scientists and film-makers, Steve's aim is to document the wildlife here and discover new species. On his first mission down river rapids and through tangled forests he discovers a bizarre venomous catfish, comes face to face with a death adder, and stumbles into a forest dripping with thousands of frogs' eggs.

Steve Backshall pushes deeper into Papua New Guinea's secret world by climbing into a vast and unmapped cave system. This underground world is flooded with raging water, and moving just a few meters is slow, hard work, but it's worth it, as each new step is pure exploration. Together with a team of expert cavers, Steve maps new passages, and discovers alien life - blind crabs and cave crickets with huge antenna. But, miles underground in the darkness, he suddenly falls ill...

Steve continues to search for new animals, this time on Mount Bosavi, an ancient volcano that last erupted 200,000 years ago. Any animals here could be entirely new to science, and so when a tiny skull is found, Steve and his teammates dedicate days and nights to trekking through the crater in search of this mystery animal. Cameras keep watch and live traps are rigged, until finally the team make a discovery that blows everyone away. Steve and the team find a beautiful new type of cuscus, an animal that has evolved in isolation here in the crater. This is a fantastic end to an extraordinary adventure in Papua New Guinea. His team back at base camp have also found over 40 new species of frogs, lizards and insects and documented hundreds of bizarre animals - proving that this is a unique wilderness that deserves protection.

Steve Backshall takes on his most deadly challenge in the swamps of Botswana's Okovango Delta. His aim is to swim with the nile crocodile, a terrifying and effective predator that has outlived the dinosaurs, and is feared today by people and animals alike. As he descends into the dark and eerie water world, he encounters an adult female and a huge male crocodile. Creeping close to get a better look, Steve is chased by the male and has to make a quick escape back to the safety of the boat.

Steve Backshall goes in search of the super-giants of the seas on this Deadly Adventure. Starting on the Californian coast he gets too close for comfort with elephant seals, as the huge males battle it out on the beaches, hoping to impress the females. Driven on by a fascination with ocean super-giants he heads to South Africa to witness the deadly tactics of great white sharks as they hunt. And finally, in the Caribbean, he tracks down the loudest animal on the planet - the sperm whale. But by swimming with these monsters of the sea, Steve discovers that they are actually gentle giants.

Steve Backshall heads to the jungles of Borneo to track down the wildlife hidden beneath the canopy. Along with a team of international scientists, experts and film-makers, he's on a mission to prove just how special this jungle is, in the hope of protecting it from destruction by loggers. His job is to find out what's living on and around Mount Kuli. But will the dense vegetation and perilous cliff faces prove too much for him and his team?

Steve Backshall continues his search for wildlife in the jungles of Borneo. This time, his quest for the unexplored parts of the rainforest take him down a 160m drop, deep into a sinkhole. Getting in there and dangling on the end of a rope pushes his bravery to the limit. Once down, the expedition venture underground into a cave never before explored by humans, which turns out to be the stuff of nightmares.

Steve Backshall heads to Bhutan in search of wild tigers. As part of a basecamp full of international scientists, film-makers and experts, his job is to find out if tigers are thriving in Bhutan's jungles. With the help of a sniffer dog, trained to track down tiger scat - or poo - he goes off in search of clues. On his journey he discovers what else is lurking beneath the canopy, from golden langur monkeys to an Indian rock python, and the extremely rare clouded leopard.

Steve Backshall continues his search for wild tigers in Bhutan. This time, his journey continues by kayak, navigating the treacherous rapids of the Drangme Chu river where he struggles to keep his head above water. His search then continues, high up in the Himalayas, on a mission to find out if rumours of tigers living at altitude are true. Up there, in the dead of night, he comes face to face with a big cat.

Steve travels to Japan to prove that it's possible to find extraordinary animals and adventure in one of the busiest countries on the planet. He kayaks through frozen seas to encounter the gigantic Steller's sea eagle, skis into frozen mountains to search for deer, takes a hot bath with Siberian swans drawn to Japan by its volcanoes, and travels south to find a monster that lurks in the ditches.

Throughout this series, Steve Backshall has travelled across the globe encountering wildlife from the cuddly to the deadly, putting his stamina and his bravery to the test along the way. In this special episode, Steve counts down through his top five adventures of the series, revealing which one he has chosen to take the spot as his top deadly adventure.