This show is concerned with technology from history that was either ahead of its time and subsequently forgotten, or artefacts which are mysteries in themselves. This includes the Baghdad Battery, where German scientist Arne Eggebrecht is shown electroplating a small silver statue with a gold cyanide solution and a replica of the battery using grape juice. There are also segments on the Antikythera Mechanism (including an interview with Derek J. de Solla Price), the Stone Balls of Costa Rica and the so-called 'Skull of Doom' which dominates the opening credits of the series. Also included are the vitrified stone forts of Scotland including Tap o' Noth near Aberdeen. Clarke opines at the end that had some of these forgotten technologies been developed and not lost that it would now be like it was the year 4000 AD and that we would have already 'colonised the stars'.
