<P> Filming of the four episodes began on September 22 , 2017 . Supergirl 's episode was directed by Larry Teng , Arrow 's by James Bamford , The Flash 's by Dermott Downs , and Legend of Tomorrow 's by Gregory Smith . </P>
<P> Filming of the four episodes began on September 22 , 2017 . Supergirl 's episode was directed by Larry Teng , Arrow 's by James Bamford , The Flash 's by Dermott Downs , and Legend of Tomorrow 's by Gregory Smith . </P>
how many episodes are in crisis on earth x
how many episodes are in crisis on earth x
four
four