Stretching along the coastline of India and Bangladesh, this complex maze of mangrove trees and waterways mark the area where land meets the sea and freshwater meets seawater.
Wildllife thrive in this unique and delicately balanced ecosystem and it is home to large numbers of mammals, birds and fish. It is also one of the largest haunts of the endangered Royal Bengal tiger.
But the Sundarbans value extends beyond just providing a habitat for these magnificent animals; it also protects the densely populated Bay of Bengal from cyclones and the worst extremes of nature.
Yet, it is now threatened by man’s activities, including land reclamation, logging and shrimp farming. In fact, this vast tract of mud and tangles of roots is now being destroyed faster than almost any other ecosystem on Earth, removing this essential barrier and the rich habitat.
In this film sustainability advisor and author Tony Juniper, environmental economist Pavan Sukhdev, and lead scientist with The Nature Conservancy Dr M Sanjayan reveal the wildlife this strange and magical forest supports and explore the hidden strengths that make it such an effective coastal defence.
If you would like to comment on this video or anything else you have seen on Future, head over to our Facebook page or message us on Twitter.