The band’s fourth album had no mention of their name on the cover, nor an album title – just four mysterious symbols to represent each band member. The painting of the wood-bearing old man was, it is said, found by singer Robert Plant in a junk shop. For the cover it was nailed to a demolished house in Dudley.

Classic licks: ‘Black Dog’, ‘Rock and Roll’, ‘Stairway to Heaven’.

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