More than 2,000 young people are gathering on Dartmoor today ready to take part in the Ten Tors challenge. Teams from schools and colleges across the region will set off on the two-day trek at 7am tomorrow (Saturday) morning.
The longest route is 55 miles and includes some of the toughest terrain and highest peaks in Southern England.
The Dartmoor Rescue Group, who have been involved in the event since it first formed in 1968, will be there if any young people need help.
Sea King helicopters have been used to help get any injured parties off the moors but for the first time the Navy's latest Merlin helicopters will be used this year. Helicopters have been part of the Ten Tors team for over over fifty years. Robert Steemson, Head Ranger Dartmoor National Park says they are expecting incidents:
The Ten Tors is a complicated military exercise with around a thousand men and women from the Army, the marines and the airforce on hand to get the event off the ground.