Being a big metal head in North America, I've always been jealous of the European's enthusiasm towards metal in general (I get the impression right or wrong, that it's as popular as pop music). The energy of this big crowd reaches almost Woodstock level.. and they're all metal fans! Would love to visit Europe someday and experience one of these huge live shows myself.
Check out this version of Valhalla by Blind Guardian at Wacken 2007. The sound quality and crowd enthusiasm is amazing (especially during the chanting, it gives me chills). For reference, this is a link to the music festival information: https://www.wacken.com/en/