1. Felicity Smoak was originally a one-episode character.
Felicity Smoak, played by Emily Bett Rickards, was only meant to appear as a guest character in season one. But Rapaport loved her. "That could have just been a one-line role but she popped,” he said.
2. There were character swaps.
Producers planned to have Brandon Routh play Ted Kord (Blue Beetle), but The CW didn’t have the rights to use him. Routh ended up playing Ray Palmer (The Atom).
3. Characters have to be *cut* out of their costumes.
Costume designer, Maya Mani, says the team will literally *cut* Katie Cassidy, who plays Laurel Lance (AKA Black Canary) out of her corset every day. The reason? To put it simply, because she’s tired and wants to go home.
4 .The exterior shots of Oliver Queen’s mansion are filmed at the Hatley Castle, located in the Hatley Park National Historic Site located in Colwood, British Columbia. It’s the castle popularly known as Luthor Mansion on Smallville.
5. But other characters have stunt doubles.
And they're pretty cool. Fun fact: Black Canary’s stunt double, Ivett Gonda, is an Olympianin Taekwondo.
6. The title of each episode is scripted in the show.
Like Smallville, and many other shows, the title of every episode is said at least once in the dialogue between characters.
7. The series was inspired by "The Dark Knight" Trilogy.
It’s hard to not see the major similarities between the two shows. Both tell the story of spoiled rich kids who become vigilantes. The visual style is also very similar to that of Christopher Nolan’s The Dark Knight Trilogy.
8. They used oatmeal as cement.
In one scene, Oliver and Diggle get trapped in wet cement. Juliana Harkavy told Marie Claire in an exclusive interview that they actually used thousands of gallons of oatmeal. “After a couple of days it started to smell putrid, and we were all gagging and laughing the entire time we shot it,” Harkavy said.
9. Characters are named after writers...
The character John Diggle was named after Andy Diggle, writer of Green Arrow—Year One.
10. and writers are alluded to through the dialogue.
Mike Grell, an iconic writer and artist of the Green Arrow comics is alluded to through a character, Judge Grell, in the pilot episode. Arrow has been known to make mention of its writers in dialogue.
11. Mike Grell also drew the sketch in the pilot episode.
Just another Easter egg the creators of the show threw in. Grell is known for his art in the comic book series, so, of course, they had him sketch“The Vigilante” in the first episode.
12. There’s a professional archery technician on set...
Anyone who touches a bow must got through training with archery technician, Patricia Gonsalves.
13. ...and Stephen Amell had to train with her for two months.
“For safety reasons, the actors must have a lesson in safety before they can shoot a bow,” she told Archery 360.
14. The arrows are hand-crafted.
Patricia Gonsalves, the behind-the-scenes archery technician, said she crafted nearly 2,000 arrows for Season 2 alone.