A lighthouse is a building with a warning light that helps boats to navigate safely, especially when it's dark or foggy. Maine is famous for its many lighthouses.
Most lighthouses consist of a narrow tower, with a rotating or flashing light at the top, located near the coast. Before the invention of the lighthouse, fires were lit on hillsides to help captains guide their ships, and after permanent ports were built in coastal areas, permanent lighthouses were constructed. These warned sailors of obstacles at sea, rocky coastlines, and harbor entrances — and their designs grew more complex through the 18th century.