My favorite part of lighthouses is the Fresnel lens they used to use. This lighthouse in Mendocino, California on the Pacific Coast is very unusual in that it still has a Fresnel glass lens. Even more unusual is the Fresnel lens still rotates and works.
This is a historical image above photographed at the Lighthouse.
Large video of Fresnel Lens turning:
Cabrillo Lighthouse in Mendocino, California: http://youtu.be/hG5t2sFXRrg