You're traveling the ocean in a ship and wondering where, exactly you are. What to do.....??
And then someone says, I know--let's build a big fire on that high hill for ships to use as a guidepost.
Thus began the lighthouse as we know it today.
If a fire was a good idea, people decided, then a building where a 'permanent' fire could be housed was even better. By the 1600s there were at least 30 lighthouses built around the coast close to Europe and England. The lighthouse, or a concept of it, was mentioned as early as the 8th century BC in The Odyssey and The Iliad.
Montazzah Lighthouse, Alexandria, Egypt
Originally the lights were meant to help navigate by, but eventually also became a way of warning ships of bad sailing conditions or hazards that lie ahead of them. Lighthouses were built as far out on a coastline as people dared, but they weren't always engineered well and could be 'taken' by the sea in a storm. There was a need to anchor them deeper into the ground and build them of masonry, brick, or concrete, which made them longer-lasting. The lights were fueled by wood, coal, or oil, and tended by people who kept the glass (lens) clean, trimmed the wick if using oil as a fuel, maintained the outside of the building, and some kept records of ships passing through as well.
Go with a couple as they climb up to the top of a lighthouse in Cape Hatteras: Notice this one has a black band around it.. https://www.bing.com/videos/search?q=tour+of+lighthouse&&view=detail&mid=7A8223C2357271D1FFD07A8223C2357271D1FFD0&FORM=VRDGAR
When a community didn't have a lighthouse, they would often have a light in the tall steeple of a church located on the coast to help ships find their way. - In 1858, the first electric-powered lighthouse was built in England.
- Some lighthouse lights revolve and some have a steady light. Some flash on and off.
- Some use mirrors to reflect more light
- Different lenses can be used to make a lighthouse more visible
- The atmosphere affects the quality of the light: Fog, smoke, haze, wind, smog--all can make it harder to see, even as bright as they are
- The light can be a maximum of 100,000 candelas. By comparison, a 60 watt light bulb used often in a table lamp, has 800 lumens or roughly 9600 candelas.
- Lighthouses are usually white, but may also be a color or black to make it more visible in the sea
- Lighthouses can be built in the sea with the right footings
- Helicopters are commonly used to do maintenance on tall lighthouses
- In the early 1900s, some lighthouses added a 'fog signal,' a low sounding horn operated by a sort of mechanical set-up. Lighthouses that use a 'horn' now are automated (unattended by people).
- In addition to lighthouses, there are light ships: these are ships that anchor in the ocean at all times and have lights mounted high on their masts for guidance. They are always automated, no people are on the lightships
- Lighted buoys also are used to help ships follow certain paths. They're anchored to stay in the sea. These buoys have color coded paint and flash color coded lights: They flash red for ships to stay to the left (port) side, or green for the ship to stay to the right (starboard) side.
- A Cardinal Buoy marks the deepest water and the safest route.
A lighthouse actually built in the ocean. (it houses a light, and that's all)
Frequently asked questions about lighthouses: https://www.us-lighthouses.com/faq.php
As of today, there are over 600 lighthouses in the United States. Only one is manned by a person, all the rest are automated. The United States Coast Guard maintains the lighthouses. Lots of interesting stuff about lighthouses:
https://www.britannica.com/topic/lighthouse
Coast Guard listing of different symbolism used by lighthouses, buoys, and other details: https://www.navcen.uscg.gov/pdf/lightLists/LightList%20V7.pdf
This is Split Rock Lighthouse on Lake Superior, in Duluth: