A gamble when it first began, Arrow not only turned into a success for the CW, it launched an entire TV franchise, becoming the crucial first component in a universe that now includes four different series (including The Flash, Supergirl and Legends of Tomorrow) airing on four different consecutive nights.

(L-R) Mark Pedowitz, Peter Roth, Katie Cassidy, Emily Bett Rickards, Willa Holland, Colton Haynes, Paul Blackthorne, Echo Kellum, Marc Guggenheim, Stephen Amell, Greg Berlanti, Andrew Kreisberg, David Ramsey, Caity Lotz, Katrina Law and Josh Segarra at Arrow’s 100th episode party - Photo credit: Bettina Strauss/ Warner Bros. Entertainment Inc.

What it Feels Like to Hit Episode 100

Stephen Amell at Arrow's 100th episode party - Photo credit: Bettina Strauss/ Warner Bros. Entertainment Inc.

How Episode 100 Honors the Past - and the Crossover

Arrow: "Invasion!" Photos 19 IMAGES

Favorite Arrow Memories

Katie Cassidy and Caity Lotz at Arrow's 100th episode party - Photo credit: Bettina Strauss/ Warner Bros. Entertainment Inc.

David Ramsey at Arrow's 100th episode party - Photo credit: Bettina Strauss/ Warner Bros.

Wednesday November 30th, the 100th episode of Arrow airs – a big deal for any series, and especially notable for shows based off of comic books, as only a handful (including The Adventures of Superman, Batman, Sabrina the Teenage Witch and Smallville) have hit that milestone before.At a celebration event in Vancouver, I spoke to several of Arrow’s creators and cast about reaching episode 100, what to expect in the episode – which is also part of the big crossover occurring with all the other CW/DC Comics series – and their favorite memories from the show so far.Arrow’s executive producers and cast had no idea the show would a hit and all expressed gratitude that the show has gone the distance in the way it has.I've been a part of shows that have gone 100 episodes but I have never been there from the start to episode 100. It's really special for me that it's this one. It's a wonderful feeling. You're really grateful, I think, for all the effort that everyone's putting in to make it stay great and last.I made a deal with myself when Greg first invited me to be part of this project that if they just filmed the pilot I would have been happy. If it turned out to be this thing that got bootlegged and was passed around at Comic-Con, that would have been okay with me. I just wanted this pilot made because I was so jazzed by the idea and fell in love with the script. The fact that we're standing here five years later after 100 episodes is all gravy to me.It's very cool, man. I really don't know how to put it into words properly because we're in the midst of a crazy shooting schedule right now. I'm constantly grateful that the show has had such a great support group and such loyal fans. And here we are. 100 eps.It's huge, I have to say. I've been on several shows that haven't hit that milestone and this is very exciting. It also goes by very, very fast. You'd be surprised. We do so many episodes and it feels like it's gone by in a blink of an eye.I’m still wondering whether I’m going to die in the 101st episode. I’m just kidding! 100 episodes of Arrow. What!? It’s dope. I mean, honestly, it feels like we started this three years ago. It really feels like it. If we could all be so lucky as to have this level of success to have a four-show crossover coming up... It’s unprecedented in television, what we’re doing. I’m happy to just do it, you know what I mean? I’m a comic book geek so I’m happy to play a comic book character but to be a part of something as big as what Greg and everyone else is doing, it’s a real treat.It’s been a really long journey but a really wonderful one. It’s been a growing process and a learning process. We’ve been lucky and I appreciate every second of it. Especially for me and my character, I think the writers wrote really well for me and gave me a lot to do and a lot to play with. I’ve been constantly challenged.The storyline for the 100th episode is particularly tricky, because it’s also the episode that is Arrow’s portion of the crossover with Supergirl, The Flash and Legends of Tomorrow. The episode not only includes all of those guest stars (including Arrow alumni like Caity Lotz and Brandon Routh), but also many faces from the show’s history, such as Katie Cassidy. While the Arrow crew couldn’t get into the specifics of the storyline (Which involves Oliver finding himself living a very different life, where many many loved ones he's lost are still alive) they did say they embraced the challenges.We knew it would fall during the crossover and then we didn't know how, until we got to the crossover, how we would still celebrate this show. And that was a big priority for us. I think it does both. I'm really proud of that element about it, that it both fits right into the four-way crossover but it really is a celebration of Arrow and also kind of in the vein and the spirit of the great what if comics. It's got kind of a fun twist in that way. I hope everybody appreciates it as much as we intended.There's so many things that fans want people to do in the 100th episode and without the crossover and without the elements the crossover brings we would not have been able to do it the way that we wanted to within the Arrow universe. The crossover, in a lot of ways, was a blessing.[The crossover] is going to be big, as expected. It's huge. The Arrow episode, I think, is particularly cool because it's very nostalgic. You get to feel everything you felt from all the different seasons. It's cool.It’s our big crossover. Diggle gets to meet Supergirl, which is incredible. It’s great. I took a picture of all the superheroes on the rooftop. You have Supergirl and The Flash and Arrow and the Black Canary and Atom and all the superheroes in the Berlanti universe. That moment I got a glimpse of “Wow, look what I’m doing, Ma!” What can I give you in terms of a glimpse into that episode? Well, a lot of superheroes are in it. We have a big bad enemy that is pretty badass. And Diggle gets to meet Supergirl! …I said that already, but it’s a big thing!I think the biggest thing was just to make sure that the fact that it's the middle part of the crossover didn't overshadow that it's the 100th episode of Arrow. 100th episodes, or anniversary shows, want to be a celebration of the show and they want to be a love letter to the fans. So we were just very conscious of, as we were telling this Invasion story, making sure that the Arrow portion of it really said something about Arrow and just didn't feel like the middle leg of a grander journey.It did happen to fall on the crossover, and as you know the crossovers bring in elements from Flash and Legends that aren't necessarily part of the DNA of Arrow specifically, so we really lucked out. Greg Berlanti had this amazing idea and came up with this very cool concept that manages to honor the roots of Arrow and also really be a nostalgic love letter to the show. It was amazing. It was an embarrassment of riches. We really had to decide who was going to be there. Who we can get is always an issue when people come and go on the show - actor availability. It was an amazing episode that surprisingly broke really easily and was really a blast to write.There were just realities that exist with actors. Colin Donnell is a series regular on a show. Colton Haynes had a lot of prior commitments. We went in with a laundry list of things we wanted to see but at the end of the day, reality does at some point have to intrude. I think we came up with a clever way to have Colin and Colton represented, but it’s a challenge. At the end of the day, you’ve got limitations on you in terms of people’s availability. But I think it’s a great love letter to the show and it represents the first 99 episodes well.With 100 episodes to choose from, I asked the Arrow team if they had a particularly favorite memory from the show – whether it be a completed episode or a behind-the-scenes experience.Episode 215, from Season 2. The all-island episode. That was one of my favorite episodes of TV we ever did. That was one of my favorite scripts and Glen Winter directed it and it came out better than we could have ever hoped. That will always remain a highlight for me.Oh god, there's so much stuff. When I look back at it, I was seeing pictures of Sara and all the different episodes, and it's pretty crazy how far she's come. If I had to pick one moment... there's an episode called “League of Assassins” in Season 2 that is really great. Paul Blackthorne, who plays my dad, we have a nice moment in that. A lot of origin story happening. That's my favorite.The scene in Season 2 when Laurel puts the Black Canary jacket on for the first time, obviously. And I feel like the overall arc for me and my character has been so well written and again, they gave me somewhere to go and something I could really sink my teeth into. I just think, overall I’m really happy about it. There’s a moment in Season 3 where my character, she’s gone through so much, and finally her and Felicity have a moment together and Emily [Bett Rickards] is one of my best friends and I just remember us together on screen and connecting as actors. It was just a nice, beautiful moment. And I feel like it lifted me up.I have a few of them. Stephen might tell you this story too. Stephen and I -- when I first met him, he thought I was a method actor. I didn’t talk a lot. I didn’t smile. So he didn’t know I like to play around. So in this particular scene, he’s sitting at the dinner table at the Queen mansion and there’s a big push by the camera into his face and I say to him -- I bend down and whisper into his ear, “Mr. Queen, your ride is ready outside.” I was his driver. So just before the [camera] push comes, I bend down and I say to him in his ear, “Mr. Queen, I have the biggest, hairiest *** you’ve ever seen in your life.” And it’s pushing into him just as I say it and ever since then, we can’t stop making each other laugh. It’s been great.Oh gosh, there’s so many highlights. For some reason tonight, I’m thinking a lot about the first season finale. That felt like a culmination of what was a very challenging and difficult year in terms of not just replicating the pilot but improving on the pilot and doing it for 23 episodes. I remember sitting there, on the set for Starling City, in the midst of the post-earthquake aftermath and we had cranes and lighting machines and it was raining and all sorts of madness and I remember thinking “What have we wrought?” It felt like a movie set. That was exciting. I think it was an important milestone for us.The pilot. The pilot. And just the communal aspect of the pilot and everyone pulling together and feeling like we were making something cool and seeing it for the first time.I really don't think anything can ever compare to the first bunch of episodes, because you're so in the weeds and you don't know if it's working. You know that you like it but you don't know if other people will like it. I can remember reading the ratings the second and third week and seeing people start to talk about the show and going to Halloween that year and seeing kids dressed as Arrow already and feeling like, okay wow, this show really could work. And then the challenges are just continuing to challenge yourself and maintain that. You can work just as hard on all that and have the best intentions and the show not work. It was a nice reward that it did.

Arrow's 100th episode airs Wednesday, November 30th on the CW.Eric Goldman is Executive Editor of IGN TV. You can follow him on Twitter at @TheEricGoldman , IGN at ericgoldman-ign and Facebook at Facebook.com/TheEricGoldman