Before electricity, lighthouses relied on lamps that would almost be considered mood lighting by today's standards. Mechanisms were clockwork and had to be wound as often as every two hours. In the 19th century, Fresnel designed a lens that could focus this light into parallel rays and project it horizontally, dramatically improving lighthouses. By the end of the century, all lighthouses had Fresnel lenses classified into orders, with first order being the largest and most impressive.
View the entire chart: the extreme architecture of lighthouses