2. Finn the Human has been voiced by two brothers
Finn the Human was voiced by Zack Shada for the first few years but as he got older his voice changed so his younger brother Jeremy Shada (pictured) replaced him
3. It takes 9 months to make 1 episode!
4. Adventure Time is coming to an end...
The series is due to finish in 2018 but it's not all bad news. Firstly, there will be close to 300 episodes by then, and secondly, they're going to wind the whole thing up with an Adventure Time movie!
5. Finn's eyes look black most of the time, but when they are shown in close-up they are very light blue
7. Although Princess Bubblegum looks young, she is in fact 874 years old!
8. Marceline the bass-playing Vampire Queen is ambidextrous
This means she can play her bass (which is made from her ancient family battle-axe) either way around
10. There's a small waving snail in every episode
Can you spot him?