WE LEFT THE 4WDs BEHIND - EMOTIONAL ending to 2,500km River Challenge

2,500km up Australia's longest river. The Murray River source is hidden deep in the Australian Alps - and Graham Cahill went Off Grid to find it in a 4WD. 

Did he make it? The Murray Darling is the lifeblood of Australia. Its source is a tiny GPS-marked spring deep in the Kosciuszko High Country - and the 4WDs couldn't get us all the way there. Steep mountains, raging rivers and brutal High Country weather pushed us to our limit on the final push to find it.