Seriously...

Two decades ago Da Vinci Code mania gripped the world. But the story behind the theory that Jesus Christ had a secret bloodline is more surprising than any thriller. Step aside Indiana Jones and Robert Langdon - BBC Paris Correspondent Hugh Schofield heads to the South of France to uncover a forgotten milestone of broadcasting which helped set the template for the modern conspiracy theory. The Lost Treasure of Jerusalem was a 1972 episode of the BBC history series Chronicle. It sets out the unusual local mystery of Rennes-le-Château - and the charismatic parish priest who somehow funded a major church renovation. What treasure had he uncovered? Written by and featuring the actor-turned writer Henry Lincoln, the programme was a phenomenon. The idea that the church was decorated with symbols and clues hinting at the origin of the unexplained wealth gripped viewers and led to two follow-up programmes. But Lincoln's research for the programmes became the keystone of the book The Holy Blood and the Holy Grail