Characters played by William Hopper
Col. Robert Calder
Characters played by Joan Taylor
Marisa Leonardo
Characters played by Frank Puglia
Dr. Leonardo
Characters played by John Zaremba
Dr. Judson Uhl
Characters played by Thomas Browne Henry
Maj. Gen. A.D. McIntosh
Characters played by Tito Vuolo
Commissario Unte
Characters played by Jan Arvan
Signore Contino - Government Official
Characters played by Arthur Space
Dr. Sharman
Characters played by Bart Braverman
Pepe
Characters played by Sid Cassel
Farmer
Characters played by Paul Cristo
Police Officer
Characters played by Noel Drayton
1st Reuters News Correspondent
Characters played by Darlene Fields
Miss Reynolds
Characters played by Duke Fishman
Fisherman
Characters played by Michael Garth
Minor Role
Characters played by Ray Harryhausen
Man Feeding Elephant
Characters played by Ronald Hyde
Policeman Shooting Flamethrower
Characters played by George Khoury
Verrico
Characters played by Richard LaMarr
Italian Townsman
Characters played by Saverio LoMedico
Minor Role
Characters played by John Marlin
Italian Townsman
Characters played by Mike Morelli
Fisherman
Characters played by Rollin Moriyama
Dr. Koruku
Characters played by George Nardelli
Townsman
Characters played by Don Orlando
Mondello
Characters played by George Pelling
Maples
Characters played by Paul Ravel
Felix Roi
Characters played by Jerry Riggio
Minor Role
Characters played by Barry Russo
American Embassy Aide
Characters played by Stephen Soldi
Italian Townsman
Characters played by John Sorrentino
Minor Role
Characters played by Paul Stathes
Police Officer
Characters played by William Woodson
Opening Narrator