The title pretty much sums up the story. Malevolent aliens in the titular vehicles try to intimidate Earth into surrendering before launching an all-out attack. Unusual for the genre, we 'fired first', (although the aliens were likely up to no good from the beginning, having shot down all of our satellites). The typical B-movie story finds scientist Russel Marvin (Hugh Marlowe) (and his pretty wife Carol (Joan Taylor)) constantly in the thick of things as the heroic boffin whips up a last minute miracle weapon. The script and acting are pretty trite, and other than Ray Harryhausen's stop-action work, the production values are weak (notably in the use of excessive and sometimes poorly matched stock footage). Some of the matte footage (such as the heroes running through the fire) is amateurish, and there are a number of irritating inconsistencies in the plot, especially with respect to the alien's capabilities. Of course, what makes the film a must see for genre fans are Harryhausen's iconic stop-action flying saucers. The design is classic, the model work excellent, the saucers are well integrated into the live action footage, and the film was one of the first to include the now de rigueur 'alien invasion' motif of trashing national monuments. Typical of Harryhausen projects, if the rest of the movie had been as good as the special effects, it would have been a classic.