Quatermass And The Pit (aka Five Million Years To Earth)

Never let is said that the Hammer Studios in Great Britain were all Dracula-based schlock. This film, based upon the BBC Quatermass television shows, was released in the USA as Five Million Years To Earth, and I snuck in and saw it in theaters when young, with my pals.

Released a year before 2001: A Space Odyssey and The Planet Of The Apes, this was the first really good sci film since Robinson Crusoe On Mars. Realistic, scary, and deeper than normal sci fi fare, it rocks.

And, it's free on Cinemension: