doctor who"Doctor Who" is one of the longest-running franchises in all of space and time -- it's been on TV, radio, and bookshelves for more than 50 years, so there's a lot to dig into. With such a long history, you can join in on the fun anywhere, anytime. Here are the best reasons to join the Doctor in his time machine/spaceship, the TARDIS, for adventures throughout the space-time continuum.

1. You Can Start Anywhere

Every fan has an opinion about the best place to start watching "Doctor Who." Some argue for beginning with the 1964 black-and-white series, and others advocate for jumping in with the more modern 2005 version of the franchise -- affectionately known as "Nu Who." Although "Doctor Who" is full of canonical rules, backstories, and in-jokes, most episodes are intended as standalone stories about the Doctor and his companions running into adventures throughout space and time. Really: You can pick almost any episode and find an enjoyable, one-off, thoughtful sci-fi feature that doesn't require a lot of previous knowledge. All you need to know is that the Doctor is a Time Lord with a penchant for dragging humans on his escapades, and he has a knack for finding trouble -- and saving the day.

2. There Are Plenty of Doctors to Choose From

Thirteen different actors have played the role of Doctor Who -- the Doctor doesn't die, he merely regenerates into a new incarnation of himself, allowing others to play the part -- and each actor puts his own spin on the role. Whether you prefer David Tennant's passion, Matt Smith's boyish charm, or Peter Capaldi's measured wit, it won't take long to claim one as your favorite -- most fans even go so far as to claim a favorite as "my Doctor."

3. It's Got Plenty of Romance ...

Although he's thousands of years older than most of the people and creatures he meets, the Doctor has been known to find himself in the midst of numerous romantic entanglements. Whether it's a brief romantic-comedy fling with Queen Elizabeth, endless flirtation with his companions, or a heist with his occasional wife, River Song -- who has been played by several actresses, most often the wickedly charming Alex Kingston -- "Doctor Who" always packs in the banter, affection, and classic will-they-or-won't-they scenarios.

4. ... And a Lot of Action, Too

Despite being a pacifist, the Doctor always manages to get himself into tense, fast-paced scenarios that leave viewers' hearts racing. He's saved Earth from alien invasions -- both from the sky and underground -- defended entire galaxies from his archrivals the Daleks, and even managed to stop entire wars. The Doctor has a host of catchphrases, but with the nearly nonstop action on the show, the most enduring is "Run!"

5. The Doctor Who Spinoffs Are Just as Good

"Doctor Who" has given rise to several spinoff series, most notably "Torchwood" -- an anagram of "Doctor Who" -- a "The Sarah Jane Adventures" is the most family-friendly spinoff, featuring one of his former companions and her exploits. In addition, the show "Class" will premiere later in 2016, and is aimed at the young adult crowd -- show-runner Steven Moffat even describes it as a "British Buffy [the Vampire Slayer]."

6. It's Good on TV, and Even Better at the Movies

Once or twice a year, Doctor Who fans can enjoy the treat of seeing their favorite episodes on the big screen, often in specialized 3-D versions. Most recently, the epic two-part Season 8 finale was shown in theaters nationwide, proving that the Doctor is even more of a spectacle in three dimensions. The 2015 Christmas special, "The Husbands of River Song," was also a cinematic delight for fans.

7. There's Always More to Binge

Normally, binge-watching a show inevitably means getting to the end, but with "Doctor Who," there's always more to watch, read, or listen to. Most of the actors from the TV show continue playing their roles in the countless audiobooks and radio plays that fans continue to gobble up. Whether you're ready for a foray into classic '60s "Doctor Who" or just want more time with your own favorite Doctor, there are enough stories to satisfy any fan for a lifetime.