Best Science Fiction Movies of 1940

Four explorers are summoned to Peru by the brilliant physicist Dr Thorkel. They discover a rich source of radium and a half-mad Thorkel who shrinks them down to one-fifth their normal size when they threaten to stop his unorthodox experimentation.

The owner of a coal mining operation, falsely imprisoned for fratricide, takes a drug to make him invisible, despite its side effect: gradual madness.

When his friend Professor Kingsely (Ridges) is at deaths door, brain surgeon Dr. Sovac (Karloff) saves his life by means of an illegal operation that transplants part of injured gangster Red Cannon's brain. Unfortunately, the operation has a disasterous Jeckll and Hyde side effect and under certain conditions the persona of Cannon emerges. Sovac soon learns of the duel personality and of half a million dollars the gangster has hidden away. He attempts to find the money through the manipulation of his friend, an attempt that brings Kingsley closer to madness as he alternates between a meek professor of english and a brutal gangster out for murderous revenge on those who tried to kill him.

Kitty Carroll, an attractive store model, volunteers to become a test subject for a machine that will make her invisible so that she can use her invisibility to exact revenge on her ex-boss.

One Million B.C. is a 1940 American fantasy film produced by Hal Roach Studios and released by United Artists. It is also known by the titles Cave Man, Man and His Mate, and Tumak. The film stars Victor Mature as protagonist Tumak, a young cave man who strives to unite the uncivilized Rock Tribe and the peaceful Shell Tribe, Carole Landis as Loana, daughter of the Shell Tribe chief and Tumak's love interest, and Lon Chaney, Jr. as Tumak's stern father and leader of the Rock Tribe.

Dr. Carruthers feels bitter at being betrayed by his employers, Heath and Morton, when they became rich as a result of a product he devised. He gains revenge by electrically enlarging bats and sending them out to kill his employers' family members by instilling in the bats a hatred for a particular perfume he has discovered, which he gets his victims to apply before going outdoors. Johnny Layton, a reporter, finally figures out Carruthers is the killer and, after putting the perfume on himself, douses it on Carruthers in the hopes it will get him to give himself away. One of the two is attacked as the giant bat makes one of its screaming, swooping power dives.

Dr. Leon Kravaal develops a potential cure for cancer, which involves freezing the patient. But an experiment goes awry when authorities believe Kravaal has killed a patient. Kravaal freezes the officials, along with himself. Years later, they are discovered and revived in hopes that Kravaal can indeed complete his cure. But human greed and weakness compound to disrupt the project.

A newspaper publisher and his Korean servant fight crime as vigilantes who pose as a notorious masked gangster and his aide.

A physician on death row for a mercy killing is allowed to experiment on a serum using a criminals' blood, but secretly tests it on himself. He gets a pardon, but finds out he's become a Jekyll-&-Hyde.