The Amazon is the largest rainforest in the world, and the richest ecosystem on earth. Spanning nine countries it covers eight million square kilometres of South America. It’s so huge, that if it were a country it would be the seventh largest in the world.

This film uncovers what makes the Amazon such a powerhouse of evolution; how it has come to home a third of all species on the planet.

The Amazon is a jigsaw of many different worlds. High in the canopy monkeys reign supreme, leaping and swinging through the treetops, ever mindful of attack from harpy eagles – the deadliest aerial predator in the jungle. Far below, on the forest floor, the unchanging environment has led to an explosion of life. Weird and wonderful forms of life exploit highly specialised niches. Army ants swarm in their millions, devouring anything in their path; even plants are part of an evolutionary arms race, developing ways to outdo rivals and threats.

People are also part of this formidable wilderness. The modern city of Manaus thrives in the heart of a rainforest that is still home to ancient cultures and witness to terrifying initiation ceremonies.

But the driving force behind this magnificent forest is the Amazon river, the largest river in the world. With more species of fish than are in the Atlantic, and boasting tributaries that are larger than most other rivers worldwide, this huge system of waterways carves up the forest into a mosaic of jungle islands.

The Amazon is a complex biological engine, the sum of many parts. But it is vulnerable to change, a vast but fragile ecosystem.