Truth, Justice and the American Way - S1-E14
Trivia: Brainiac 8 (also called Indigo) is a fictional superheroine in the DC Comics Universe, who is later revealed to be a supervillain. The character's first appearance was in Titans/Young Justice: Graduation Day #1.
Blood Bonds - S1-E9
Trivia: The door that Max opens with the alien inside has the number 52 as a reference to "the new 52" DC comic book series.
Trivia: At the end, Kara says to her sister "don't watch Homeland without me." David Harwood, who plays Hank Henshaw (the head of the Department of Extra-Normal Operations) also played David Estes on Homeland, and Melissa Benoist appeared in two episodes of the show.
Trivia: Supergirl saves a school bus full of children just as it is about to fall of the bridge, a nod to the movie Superman, starring Christopher Reeve.
Answer: For one, it's usually cheaper to film in Vancouver because of the tax breaks. But all the CW Arrowverse shows (with the exception of "Black Lighting") are/were filmed in Vancouver. So it makes it easier and cheaper for sharing set designs, crossovers, etc ("Black Lightning" filmed in Vancouver during its crossover). Originally "Supergirl" wasn't part of the Arrowverse when it was on CBS, but it was too expensive to produce and wasn't reaching the wider audience the CW shows had. So CBS moved it to its sister company, The CW.
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