Five-part documentary from the History Channel which explores unexplained phenomena spanning thousands of years. Travelling to Peru, Iraq and Mali, experts seek out evidence of a possible alien presence in ancient times. The scientists uncover artefacts and use DNA technology to examine remains. Interviews with scholars and paranormal enthusiasts are also included in the show. The episodes are: 'Evidence', 'The Visitors', 'The Mission', 'Close Encounters' and 'The Return'.