Helloween

Alongside Switzerland's Celtic Frost and Sweden's Bathory, Germany's Helloween are possibly the most influential heavy metal band to emerge from Europe during the 1980s.

By taking the hard-riffing and minor-key melodies handed down from their metal forebears and infusing them with the speed and energy introduced by thrash metal, Helloween crystallized what is now known as power metal.

The group hit their commercial peak in the late '80s with the release of the two-volume Keeper of the Seven Keys, which helped make them the benchmark by which most power metal bands are measured.