I am a huge fan of the unknown. Part of what makes it so fascinating is that while it is unknown it is often thought of as only something weirdos like. But then it becomes a proven fact and, while you may not get the credit for knowing about it first you know inside that you had the courage to believe.
Many of the animals that we would never question as real; the panda, the gorilla, rhino, and okapi have one thing in common. They were once though to be what is called a cryptid.