Columbo is a reverse whoddunnit every episode, which is also so cool. Best episode is probably any old port in a storm, but they're all great. They're all standalone, so you can watch in any order you'd like

Each episode is a TV movie, so they're all about an hour. Columbo was on a rotation with 2 other mystery shows doing the same thing at the time. So it aired once every 3 weeks and was longer and higher budget than most tv. So just be prepared for a longer sit. The first episode is based on the stage play the character came from and was meant to be a one off and then theres a pilot movie, whixh are both great but theres kind of a season 0 to look for that way. First episode of season 1 is directed by Spielberg before he was famous