Hey, hey, mama -- have we got some little-known facts about Led Zeppelin for you: In this edition of You Think You Know Classic Rock?, we open up the case file for one of the greatest bands to ever wield the hammer of the gods, and find a few bits of trivia that may surprise even the most hardcore Zep fan.

For starters, there's the story behind Robert Plant's journey into the lineup. Plant actually wasn't the first choice for the group's lead vocalist position -- guitarist Jimmy Page wanted a different young British singer, but he was already committed to a tour opening for Cream, so he reportedly suggested Plant instead. Page had yet another singer in mind, but his offer was met with a violent refusal, so he eventually gave in to destiny and hooked up with the guy who was meant to hold the mic for the band all along.

And then there's the time Zep utility player John Paul Jones was hired to score a string arrangement for one of England's biggest rock bands, and came away calling the other group "boring" and "unprofessional." The song turned out to be a hit anyway, but what's the name of the band that caused Jones to turn up his nose? We've got it all right here in the video at the top -- just watch to find out.

You'll also get the scoop on Page's childhood career aspirations, which -- unlike many a future young Led Zeppelin fan -- had nothing to do with playing searing guitar solos in front of thousands of screaming fans. Instead, he had something far more serious in mind, and we reveal all right here in this clip. You think you know Led Zeppelin? You're about to find out.