Wacken Open Air

You're standing at the grounds of Wacken Open Air, in the small village of Wacken in Schleswig-Holstein, in the north of Germany. When there's no festival on, it's hard to picture. But every year in early August, tens of thousands of metal fans gather here, from more than 80 countries. It has been called the biggest metal festival in the world, even the Mecca of heavy metal.