The third and best of the Quatermass films. The other two are THE CREEPING UNKNOWN and ENEMY FROM SPACE. In this film an alien spaceship is unearthed during construction work in a London subway. At first, it's thought to be an undetonated bomb from WW II, but then scientists realize it's a Martian spacecraft that is protected by a mental energy. They tap into the energy and discover that the aliens started the evolution process to make better slaves out of apes. The Martians died, and man was left on his own. The scientists also find a device inside the craft that incites violence in people and they accidentally let loose a destructive monster on London, which one of the scientists destroys at the cost of his own life. This film was followed by QUATERMASS CONCLUSION.