Quatermass And The Pit (1967)

During excavations in London a large unidentified object is unearthed. It defies definition although the area has always been associated with diabolical evil. Within its walls Professor Quatermass (Keir) discovers the remains of intelligent alien creatures that attempted to conquer the Earth in prehistoric times and, through their experiments on early man, altered human evolution to its present state. Though dormant for many centuries, the power supply from the excavations is being drained by the ship until its terrifying force can be unleashed and the creatures can reinstate their violent dominance over man.

Adapted by Nigel Kneale from his original BBC TV serial.