What makes an album cover bad? Better yet, what makes one truly terrible?

To paraphrase US Justice Potter Stewart musing on what is 'pornography': "I can't tell you what obscenity is, but I know it when I see it."

And MusicRadar knows a bad album cover when it sees one…

Today, MusicRadar kicks off a series called The Worst Album Covers Ever, with our first installment shining a harsh light on the world of heavy metal. The songs may rock, the singers may scream, the solos may impressively shred.

But what the hell is happening with these album covers? Oh, and warning - a few of these verge on the NSFW.

All of them however verge on the terrible…