Around two thousand four hundred teenagers setting off on one of the greatest challenges of their lives - and it's something they've been training for, for months.
They'll be testing their navigational skills across 35, 45 or 55 miles of moorland. They're carrying all their own food, water and bedding - and they have to complete it without any help from adults.
But just as inspiring as those in the Ten Tors are these 300 young people with physical or educational needs taking part in the Jubilee Challenge. They take on routes of up to 15 miles - inspirational stuff for even the hardiest of soldiers.
And nursing blistered toes but memories to last a lifetime the first of the Ten Tors participants should begin to arrive back at Okehampton camp at around 8am tomorrow morning.