Five Steven Spielberg movies have been about aliens, including Close Encounters of the Third Kind and Disclosure Day, but which of them is the best?

Steven Spielberg has made many sci-fi movies, from 'Disclosure Day' to 'Close Encounters of the Third Kind' to 'E.T.'

Steven Spielberg’s fourth film about alien encounters is “Disclosure Day,” following “ET: The Extra-Terrestrial,” “War of the Worlds,” and “Close Encounters of the Third Kind.” That inspired us to take another look at what Roger Ebert thought about some of the most famous and infamous alien movies,

"Disclosure Day" director Steven Spielberg has said that his latest film, which sees him return to the topic of UFOs and extra-terrestrial life forms, is "built on a foundation of truth." Few directors have explored onscreen over the years the possibility of life on other planets more thoughtfully than Spielberg,

From the mystery of Cloverfield's Clover to the changing fury of the alien xenomorph, these are the best and most memorable monsters in sci-fi movies.

Some sci-fi movies from Hollywood history are so good that they've managed to influence several generations of filmmakers since their debut.

"We did about five scripts, and finally Steve and I compromised," Lucas recalled.

Exclusive: What makes a great science fiction movie? Prof. Lisa Yaszek dives into the commonalities among iconic sci-fi movies across the decades.