Riccardo Freda, working under the pseudonym Robert Hampton, directed this 1959 black-and-white Italian SF feature in a Mexican setting (filmed in Spain) about a radioactive glob discovered in a subterranean pool near Mayan ruins. Mario Bava (also under a pseudonym) shot the film; the stars include John Merivale, Dioi Perego, and Giacomo Rossi-Stuart. (JR)