The obstacles Pink Floyd ran into ahead of their 1967 U.S. debut were only a small sampling of what was to come.

You've listened to The Beatles and you've heard Jimi Hendrix, but don't sleep on these three slept on psychedelic rock albums from the 1960s.

When you buy through links on our articles, Future and its syndication partners may earn a commission. "It's unlike anything we've ever done before," said Syd. "It's a new sound. Got a lot of guitar ...