He’s been keeping Gotham safe for 80 years — and Saturday night, Gotham said thank you.

Hundreds gathered in Brooklyn to see a giant Bat-Signal beamed onto Williamsburg’s Domino Sugar Refinery — commemorating eight decades of the Caped Crusader.

Peopled flocked to the waterfront Domino Park to celebrate Batman Day and personally shake the hand of their brave hometown hero — one pint-sized fan even bringing his pooch dressed as the famous superhero.

NYPD Commissioner James O’Neill joined the celebration — changing his Twitter account description to “James Gordon, Commissioner of the Gotham City Police Department.”

Gordon, a main character in the Batman universe, would frequently flash the Bat-Signal to alert Batman of impending danger in Gotham.

On Saturday night, O’Neill tweeted an image of the Bat-Signal, writing: “You’d think I could just tweet at our favorite aging caped crusader instead of using this massive spotlight.”

Cities around the world joined in celebrating the annual event by displaying the Bat-Signal — the superhero’s famous distress call — onto buildings and into the night sky, delighting fans in Tokyo, Montreal, Melbourne, Rome, London, Barcelona and Berlin, CNN reported.

Batman Day is celebrated every year on the third Saturday of September but this year’s celebration was extra-special — marking 80 years since the crime-fighter also known as Bruce Wayne first appeared in the DC Comic universe.

It’s unclear why the annual event doesn’t have a specific date, but the purpose of Batman Day is to celebrate the anniversary of the Caped Crusader’s first ever appearance in Detective Comics #27 in May 1939.

Wayne’s fictional hometown of Gotham has become an enduring nickname for New York City — Batman creator Bill Finger modeling the superhero’s gritty residence after the Big Apple.