A monster movie (also called a creature feature or giant monster movie) is a movie with humans trying to stay alive in attacks by very large monsters. Monster movies can fit in the horror, fantasy, or science fiction genres. In Japan, large monsters are called kaiju.
In many monster movies, the monster is created by humans because of something such as a bad experiment, the effects of radiation, or the destruction of habitat. Since the 1953 movie The Beast from 20,000 Fathoms, many monster movies have shown the monster being created by nuclear warfare. One of the most well-known movie monsters, Godzilla, was created by a nuclear weapon. Godzilla has appeared in 28 movies and has become a cultural icon in Japan.