Strawberry Fields Forever.

Yes, that’s the B-side. The single “Penny Lane” / “Strawberry Fields Forever” is one of the most famous double A-sides in rock history, but technically “Penny Lane” was the A-side in most territories.

The Beatles recorded them during the Sgt. Pepper sessions, and the label wanted a single. They paired the two songs because they couldn’t decide which one was stronger. If you only know one, you probably know the other too. It’s a damn good problem to have.