The Lighthouse Commission's plan for lighting France's coasts would not have been possible without a revolutionary innovation – the lenses invented by Augustin Fresnel (1788-1829). It was no accident that Fresnel chose Cordouan for testing his new invention. Sailors judged it by the yardstick of the eighteenth century's most successful lighting system, Lenoir and Borda's parabolas installed at the top of Teulère's magnificent tower.