WWF holds Blue Mile event to raise awareness about man's impact on water
4 September 2011 Last updated at 09:39 BST
The world's rivers, oceans and lakes are home to an astounding array of fish, animal and plant life but they are under threat from man's activities.
As part of its latest fundraising campaign the World Wildlife Fund is asking people to complete a sponsored mile on, in or near water.
Rachel Bloodworth from WWF and explorer Paul Rose discussed the exercise, and why they are doing it.