It's no joker. 

The night sky all over the world is lighting up Saturday with an illumination of the famed bat insignia to mark a special anniversary for Batman.

DC Comics is carrying off a celebration of Batman Day to mark the 80th anniversary of the appearance of crimefighter Bruce Wayne and his masked hidden identity.

Fan gatherings are planned all over the world. But the most ambitious party plan is the illumination of the Batman signal.

It will start at Fed Square in Melbourne, Australia. It will also appear in 13 cities, including Tokyo, Berlin, Rome, Paris, London, Sao Paulo and Johannesburg.

It will light up at the Domino Sugar Refinery in New York City before making its final appearance in Los Angeles at City Hall.

(Cover: File photo, Tony Bradshaw, of Los Angeles, dressed as Batman, poses in front of a Bat Signal projected onto City Hall during a tribute to "Batman" star Adam West in Los Angeles in June 15, 2017. /AP Photo)