Black Sabbath's farewell concert, which included hits like "Iron Man" and "War Pigs," comes as the rocker is living with Parkinson's disease.

Sometimes it's easy to assume that all famous people know each other. But until Saturday's (July 5) Back to the Beginning blow-out final show honoring Ozzy Osbourne and Black Sabbath, the Prince of Darkness had never met Guns N' Roses singer Axl Ros e. Despite both men being hard rock royalty, their paths had somehow never crossed.