Superman chose to be a journalist, so it made sense for him to be the first to know about breaking news and always be running about
Superman was modeled on swashbuckling 1920s movie star Douglas Fairbanks.
Superman couldn't always fly, hence the phrase "able to leap tall buildings in a single bound." It was decided in the 40s that Superman could take off into the air
Kryptonite was invented because Superman's original voice actor wanted time off, and the only way to do this was to make Superman sick.
Bruce Wayne is part owner of the Daily Planet where Clark Kent works, so essentially, Batman is Superman's boss.
Superman was originally created as a villain bent on world domination.
Nietzsche’s philosophy was in fact the inspiration behind Superman ( originally 'The Superman') a telepathic tyrant who was later rewritten into the hero we all know today
In 1947, the Superman radio show did a series called "Clan of the Fiery Cross" in which they exposed many of the KKK's most guarded secrets. Within two weeks of the broadcast, KKK recruitment was down to zero.
Batman has beaten Superman more than once.
Superman was originally an anti-government vigilante fighter who once destroyed a slum to force the government to build better housing for the poor.