High Quality Content by WIKIPEDIA articles! The Gibbs Hill Lighthouse is the taller of two lighthouses on Bermuda, and the first of only a few lighthouses in the world to be made of cast-iron. This is because at that time, steel still was not able to be bent. The optic consists of a Fresnel lens from 1904 revolving on steel bearings. However for most of its history, the lens revolved on a bed of 1,200 pounds of mercury. While it is certainly not extremely tall in lighthouse standards, the hill that it stands on is one of the highest on the island. The light`s focal plane on Gibbs Hill Lighthouse, therefore, is at 354 feet (108 m) above sea level. Single-engined airplanes can see its flashes from over 100 miles (160 km) away. The lighthouse has 185 steps to the top in eight flights. Until 1964, most of the light was run by hand, but in June of that year, the whole system was automated and runs on electricity. Sixty-thousand people ascended the lighthouse in 1985, and it continues to be a popular tourist attraction.