Former Royal Marine Monty Halls and class climber Leo Houlding are not just exploring the unknown, but getting to grips with the ecology and wildlife that surrounds them.
In Guyana's western highlands hides Oshi and Kamarang, waterfalls three times higher than Niagara Falls. Monty and Leo lead an expedition to this lost world.
Monty Halls and Leo Houlding aim for the highest possible point, and the remotest possible part, of the Guyanan rainforest to explore new wildlife and terrain.
Deep in the Borneo rainforest, Monty and Leo attempt to scale a 300 metre cliff in the Melinau Gorge to survey its unexplored wildlife.
Beneath Borneo's rainforest lies one of the world's largest cave networks. Monty and Leo hope to uncover more than the 300km of tunnels so far surveyed.