Currency derives value not from the preciousness of the substance of which it is made, but trust in the government which issues it.
A young Venetian merchant named Marco Polo wrote a remarkable book chronicling his travels in China around 750 years ago. The Book of the Marvels of the World was full of strange foreign customs Marco claimed to have seen. One, in particular, was so extraordinary, Mr Polo could barely contain himself: "tell it how I might," he wrote, "you never would be satisfied that I was keeping within truth and reason". Marco Polo was one of the first Europeans to witness an invention that remains at the very foundation of the modern economy: paper money. Tim Harford tells the gripping story of one of the most successful, and important, innovations of all human history: currency which derives value not from the preciousness of the substance of which it is made, but trust in the government which issues it.
Presenter: Tim Harford
Producer: Ben Crighton.