How could dragons—imaginary animals—exist in cultures all over the world? For millennia, storytellers have recounted tales about mysterious creatures, but the vivid human imagination is only part of the story. Accounts from classical Greece, Europe, North America, and China tell of physical evidence taken as proof that fabulous beasts once really existed. Explore puzzling natural evidence that led people to believe in dragons, griffins, and other fantastic creatures. Did ancient discoveries of dinosaur fossils play a role?