Did you know...
...that Lt. Columbo was originally played by another actor? Whoa. How could anyone besides our beloved Peter Falk fill those wonderfully quirky shoes (or rather trenchcoat)?
I guess we all think of Columbo as a pretty happening late 60s/early 70s kind of dude, but he actually made his mark all the way back in 1960 on a series called The Chevy Mystery Show which featured unique conundrums every week (not completely unlike the NBC Mystery Wheel concept Columbo was made famous on. Every week was a total stand alone episode, featuring only one or two main characters who rotated during the season). An actor named Bert Freed got the distinguished honor of giving this guy life.
I won't pretend to know more than that, but check out this Columbo fansite where they pretty much give you all the goods you could ever want to get on the subject.