The Flash, the original Barry Allen version, made his first appearance in comics in Showcase #4, marking the character's debut and the beginning of the Silver Age of comic books.
The 2009 comic series 'Flash: Rebirth' by Geoff Johns and Ethan Van Sciver relaunched Barry Allen's story, reestablishing him as the primary Flash and revitalizing the character's role in the DC Universe.
The Flash TV series starring Grant Gustin premiered on The CW, becoming a significant and long-running adaptation that increased the character's mainstream appeal.
The Flash's standalone feature film starring Ezra Miller was released, marking a major live-action cinematic portrayal of the character and impacting his presence in the DC Extended Universe.