In 1876 John Warne Gates described the new product he hoped to sell as "lighter than air, stronger than whiskey, cheaper than dust". We simply call it barbed wire. The advertisements of the time touted it this fence as "The Greatest Discovery Of The Age". That might seem hyperbolic, even making allowances for the fact that the advertisers didn't know that Alexander Graham Bell was just about to be awarded a patent for the telephone. But - as Tim Harford explains - while modern minds naturally think of the telephone as transformative, barbed wire wreaked huge changes in America, and much more quickly.

Producer: Ben Crighton
Editors: Richard Knight and Richard Vadon. Show less