As soon as the first drum beats and guitar chords are fired, the chaos comes alive. The crowd becomes a whirlpool of flying limbs, bopping heads and distorted gestures. The mosh pit starts expanding and contracting as people shove at each other with ever more reckless strength.
Crowd-surfers glide towards the stage and performers plunge themselves into the crowds.
There is something about loud, fast, basic guitar music that awakens a primal impulse in people and drives them to dance, jump and fight with an energy and abandon that nothing else can match.