In the second of his series of ten historical detective stories James Burke takes a look at 2,000 years of human ingenuity, searching for the clues that link the bright ideas of the past with the world we live in. What is the connection between Arab pirates and the doctor at the court of Queen Elizabeth I? Or between sulphur balls and the mariner's compass? Why did dawn on Ben Nevis trigger off the invention of a 20th-century terror weapon?
(First shown on BBC1)