Then there’s the sheer resonance of the supporting characters. Batman inarguably boasts the most compellingly crazed and tragic pantheon of villains in comics history, while Superman gave us the quintessential megalomaniac baddie in the form of Lex Luthor, as well as the most appealing of all superhero romances in the bumpy dynamic between Clark Kent and Lois Lane.

But the strength of their symbolism, and the powerfully drawn characters, isn’t quite enough to explain why everyone – even people who couldn’t tell you Iron Man’s real name, and wouldn’t know their Doctor Doom from their Doctor Octopus – can readily reel off the basic facts about Batman and Superman. Don’t point to comic sales either – it’s easy to forget that the biggest superhero of the 1940s wasn’t Batman OR Superman, but a big muscle-bound chap called Captain Marvel. (Whose alter-ego was a young boy. Yes, exactly like Bananaman.)