The weapons could attack people, tanks and aircraft
Coalition forces have destroyed a huge weapons dump in caves believed to have been used by fleeing al-Qaeda and Taleban fighters.
We flew into the mountains on board an RAF Chinook helicopter, opposite a small team of Royal Marines who were joining their colleagues in the mountains.
One airman sat in the open back of the aircraft, his legs dangling over the lip of the doorway, his hands on the heavy machine gun that pointed towards the ground.
Another gun was being manned towards the front of the aircraft. In the mountain range below us, thousands of coalition troops were searching for al-Qaeda fighters and their weapons.
In a cave on a mountain more than 7,000 feet above sea level, I was shown one of the discoveries made by British Royal Marines.
In body armour and helmets we walked through the metal door of the cave, blown open by commandos earlier.
A safe walkway had been cleared through the man-made cave, pick marks were clearly visible on the walls and the roof of the 40 metre long tunnel.
We clambered across steel tubes containing anti-aircraft rockets and the commandos told me they reckoned the four caves like this contained about 35,000 rockets, shells and mortars. There were countless bullets too.
The ammunition was made in Russia and China, some had been primed ready to be fired.
Difficult breathing
The commando engineers massaged plastic explosive in their hands.
It was white and handled like children's modelling clay, but this was deadly stuff.
Sweat broke out on the faces of the team preparing the charges and they ran out the detonation cord, which burns incredibly fast.
All four caves - one named Jessica after a marine's daughter -were to be blown at once.
We followed the men of 45 Commando up the mountainside, moving more than half a mile from the caves to avoid the blast.
I carried my pack on my back - it was heavy, but a fraction of the weight the marines had carried through the mountains for almost two weeks.
The terrain and the thin air so high up quickly took their toll - I have never breathed so hard and struggled so badly.
"Firing now" rang out across the valley and for a moment nothing happened.
"Is that it?" I thought. Then the earth shook, something invisible hit me in the chest and I saw flames leap a hundred feet or more into the air.
A cheer sounded as the marines celebrated their part in the war on terror and a cloud of dust drifted beautifully over the valley, the smell of gunpowder filled the air.
As shells flew through the air from one of the caves the troops beat a hasty retreat to a safer distance.
Small explosions continued sporadically and we waited for them to stop. They didn't.
Helicopters wouldn't be able to come to pick us up with the danger of shells and rockets flying through the air and we faced a night in the open.
With water running short we prepared to sleep rough, as the marines had since the beginning of Operation Snipe.
No torches allowed, voices kept low, this would be the front line if the enemy were visible.
To the sound of explosions, and the smell of gunpowder burning, I went to sleep under the stars, tracking the satellites moving across the sky.
One of the engineers suggested they call for the map-makers and joked they had remodelled the Afghan landscape. It was not far from the truth.