By the end of the 1980s, Metal had become too commercial for some fans, with groups like the W.A.S.P., Hanoi Rocks and Poison having huge success. Influenced by the New Wave of British Heavy Metal, another new sound had risen to prominence in the US, where metal had a huge following: thrash metal, a style that went beyond in many respects, being faster and heavier than anything that had come before. But playing the guitar ever faster had reached a ceiling and at the turn of the decade, Metallica, one of the inventors of thrash, decided to turn that around and adopt a very slow, heavy, sound. The result was 'The Black Album' which went on to sell over 15 million copies and "proved that metal, never in fashion, but never out of fashion, will always just keep on going".