Four hundred teams of young people from across the west country descended on Dartmoor for Ten Tors.
They spent months training for the annual army challenge.
The event began at 7 am on Saturday morning, with each of the teams walking 35, 45 or 55 miles across rugged terrain, and completely self-sustained, with no smartphones or tablets.
The first all-female team to cross the line said they were delighted with their finish.
"It was tough, but we beat all of the goals and all of the timings that we wanted, so really happy with it," one team member said.
While Ten Tors is for young people, it is also a huge test of resilience for the hundreds of service personnel supporting it.
Air support was provided by 846 Naval Air Squadron from the Commando Helicopter Force.
Lieutenant Commander Andy White, Detachment Commander 846 Naval Air Squadron, praised the event.
"It's excellent training for our guys because they're out there doing live-tasking," he said.
"It's reactionary, so they're given a task to execute quickly, safely and efficiently so it's about as good training as we can get."
Next year the event will mark its 60th anniversary.