"Batman Day" is an annual event organized by DC Entertainment to celebrate and promote the costumed crime-fighter 'Batman', with the animated films "Batman Beyond: Return of the Joker", "Batman: Mask of the Phantasm, "Batman: The Dark Knight Returns" (Part 1/Part 2), and "Batman: Under The Red Hood", now streaming on HBO Max:
"...the first 'Batman Day' was July 23, 2014. This was the year of the 75th anniversary of the first appearance of 'Batman' in 'Detective Comics' in 1939.
"The day was chosen to coincide with San Diego Comic-Con. Subsequent 'Batman Days' have been on the third Saturday in September..."
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