The lens that saved lives. The most important part of a lighthouse might be one of the beautiful tools hidden inside of it: the Fresnel lens, a breakthrough that changed seafaring and saved lives. As the above video shows, these lenses satisfied a need for lighthouses that could shine farther and through dense layers of fog. The Fresnel lens, invented by Augustin-Jean Fresnel, helped do that by capturing all the light coming from a lamp, then magnifying and steering it in one direction. Suddenly, lighthouses became more useful and shipwrecks diminished. Fresnel lenses are still in operation today. According to the US Lighthouse Society, more than 75 Fresnel lenses are in use in American lighthouses, and businesses such as Dan Spinella’s Artworks Florida craft replicas that capture the beauty — and functionality — of the 19th-century breakthrough.