Weird Science #15

A group of Earth explorers land on Mars and find the planet devoid of life. They also find the remains of an ancient city buried under the sand. When they enter some ruins, they see a hologram of an Earthman fighting a Martian creature. They later discover that they are in a movie theater and when they are able to work the hologram projector, they find that the Earthlings are the real monsters in the film.