quatermass and the pit (1967)

aka Five Million Years To Earth.
The third Hammer Quatermass film. This time Quatermass gets irascible when workmen in the London underground discover skeletons of what appear to have been subhuman creatures. Things get even more interesting when they then discover what could be a spaceship.
My favourite of the three Quatermasses is an interesting mix of Sci-fi and horror and wonderful Barbara Shelley.