MUMBAI: UK pubcaster The BBC's Natural History unit, in partnership with Discovery, is venturing into remote rainforests, high mountains and raging underground rivers to uncover the mysterious landscapes of Guyana and Papua New Guinea, in two epic Expedition series.

It will be shown on BBC One in 2008.

Expedition Guyana: Hidden on the northern coast of South America, the forgotten country of Guyana holds some of the most extraordinary jungle on Earth. With the forest currently under threat from loggers and their chainsaws, the Expedition Guyana team aims to discover new species in order to help Guyana protect its environment.

Living rough in a jungle camp alongside local conservationists, the team will track the animals from high in the canopy to deep within the rivers. They are in search of the giants of Guyana including the anaconda, jaguar, giant anteaters, giant turtles and the enormous Harpy eagle. Working in a pristine jungle, which has been earmarked for logging or oil exploration, the cameras will be rolling every step of the way.

The series producer Steve Greenwood says, "This incredible habitat is completely unspoilt and we're sure it is home to some remarkable creatures. We'll be spending a month tracking them down and capturing them on HD. We've got all the latest camera technology to help us: thermal cameras, remote cameras, micro and underwater cameras – but in the end it will be old fashioned field skills that are most needed to survive and find the animals in this tough jungle."

Expedition New Guinea: New Guinea is the most species-rich island on the planet but its landscape is so inaccessible that much of the wildlife is barely known. Recent exploration has hinted at new and utterly unique species with strange adaptations thriving in the dense forests, in the depths of the impenetrable swamps and perched on the edges of the active volcanoes.

Hidden deep within this island is the deepest mystery in the whole of the tropics. A series of colossal caves pepper the hillside, most of them completely unexplored. Joined by world experts in extreme caving, the Expedition team take on this stern and drastic environment providing true and original exploration, captured on camera as it happens.

Running in parallel, other members of the expedition team will explore the rugged rainforests that drape the mountains. These missions include journeying up the Sepik River to meet the Crocodile People and the 26-foot crocodiles they share the river with; searching for strange birds of paradise, capturing on camera their bizarre rituals and mating behaviours; and exploring for Queen Alexandra birdwing butterflies, the largest butterfly in the world and one that is rapidly declining towards extinction.

The show's executive producer Tim Martin says, "New Guinea will be our toughest expedition yet. Sheer mountains and tangled forests make its interior hard to navigate and disputes between rival tribes are an added complication we'll have to cope with. But the rewards should be great – birds of paradise, tree kangaroos and whole forests that scientists have yet to investigate. And beneath the ground lies a vast system of caves, much of which has never been explored.

"The observational style of our Expedition brand, as seen on Expedition Borneo, Amazon Abyss and Pacific Abyss, captures the dramas of expedition life and gives a real sense of what it's like to explore some of the world's last great wildernesses. Tourists and film crews tend to visit the same well known National Parks and our approach is to go much deeper into the wilds, to places that haven't yet felt the impact of humans."