The lighthouse aided maritime pilots when at sea. One of the oldest known structures was built by the Romans; a lighthouse called The Tower of Hercules. Other reminders of these beacons of light exist on coins and in mosaics such as the many depictions of the Ostia Lighthouse.
The light had to be protected during gales. It is likely glass windows and large mirrors helped to project the light beam as far as possible. As navigation improved lighthouses expanded slowly into Western and Northern Europe. One of the oldest is Hook Lighthouse, County Wexford, Ireland.
The Later Middle Ages heralded such innovations as the Argand lamp, the Fresnel lens and one of the first parabolic mirrors turned by clockwork.
In 1836 reforms were instituted by way of the Lighthouse Act though owners still collected large dues. One infamous case included the buying back of leases for over 1 million pounds, 444,000 pounds just for the Skerries Lighthouse in 1716. This Lighthouse still stands at Carmel Head Wales fully automated, solar powered, with a range of 29 nautical miles.
An active 20th century lighthouse is found at the southern end of Ramsey Bay on the Isle of Man – Maughold Head Lighthouse. It was completed in 1914 and became fully automated in 1993.
Though fascinating why do we still use them? GPS exists. Why pay for the upkeep of obsolete technology? In the eyes of many modern mariners and in the eyes of the United States Coast Guard they are still a useful guide.
Finally, if you should set sail and suddenly find yourself in the Bermuda Triangle and all your equipment went dead at once you could still rely on this ancient technology to guide you home.