Time travel has been popping up within TV shows for a very long time. But the the first series that I personally remember that was dedicated to time travel was The Time Tunnel (1966). It involved physical transit into the past. Much later, and more successful, was Quantum Leap, from 1989-1993. How time travel works in that show is a little puzzling. Undoubtedly, the most famous time travel show of all is the venerable Doctor Who. It also has to be the most enduring such series, having begun in 1963, though it has appeared in a number of incarnations. I have no idea how many time travel themed TV shows there have been, but according to this webpage there have been at least 21. Among time travel shows currently in production, my favorite is Legends of Tomorrow. It started out as a more or less serious superhero show, but later evolved into a more fun, quasi-comedy. Actually, due to the pandemic, Legends has been off the air for many months, but there are two relatively recent time travel series that I've been streaming, almost in parallel: Travelers and 12 Monkeys. The former involves sending a person's consciousness back in time and overriding and erasing that of the target body. 12 Monkeys literally sends back and forth physically to different points in time. Travelers is a decent show, but, in my opinion, 12 Monkeys is excellent. I actually prefer it to the movie (Bruce Willis). The comparison is a little unfair, of course, as the movie had to tell its whole story in a little over two hours, while the TV series had 34 episodes, 45 minutes apiece. What are some of your favorite time travel themed TV series?