1. Batman's butler, Alfred, was not always a butler. In his first appearance in Batman #16 (1943), he was portrayed as a bumbling detective.
2. In the early comics, Batman carried a gun and was not averse to killing criminals. This changed with the introduction of the Comics Code Authority in the 1950s, which banned graphic violence and other controversial content.
3. The Batmobile has gone through many different designs over the years, but one of the most unusual was the "Batmobile on ice" from Batman #59 (1950). This version of the Batmobile had skis and was used to chase criminals across a frozen lake.
4. Batman's arch-nemesis, the Joker, was originally supposed to be killed off in his first appearance in Batman #1 (1940), but editor Whitney Ellsworth decided to keep the character around.
5. In the 1960s TV show, Batman was played by actor Adam West, who had to wear a special "Batusi belt" to keep his cape from flying up during dance scenes.
6. Batman has had many sidekicks over the years, but one of the most unusual was Ace the Bat-Hound, a crime-fighting dog who first appeared in Batman #92 (1955).
7. In Batman #404 (1987), Frank Miller's landmark series "Batman
8. The Bat-Signal, which is used to summon Batman to action, was first introduced in Detective Comics #60 (1942).
9. In Batman #497 (1993), Bane famously broke Batman's back, leading to the "Knightfall" storyline in which Batman was temporarily replaced by a new hero named Azrael.
10. In the "Dark Knight Returns" series by Frank Miller, which was published in 1986, Batman comes out of retirement to fight crime in a dystopian future.