Ben 10 is an American animated series that first aired in 2005. The series is about a young hero named Ben Tennyson, who comes into possession of an alien watch that gives him the ability to transform into 10 different alien forms, each with different powers and abilities. Ben uses his new powers to protect the world from dangerous threats.

The series has been a huge commercial success and has built a large fan base around the world. It has also inspired numerous sequels, feature films and merchandise. "Ben 10" is considered one of the best-known franchises in children's entertainment.