The first U.S. spaceship to Venus crash-lands off the coast of Sicily, freeing a small native Venusian creature called the Ymir. Eventually growing to enormous size, it threatens the city of Rome. Starring William Hopper, Joan Taylor, and Thomas Browne Henry. An early Ray Harryhausen special effects movie with a dinosaur from outer space with the final battle taking place at the Colosseum in Rome.
