Lighthouses are most well known for alerting sailors to hazards and coastlines during the night, or through conditions that impede visibility, such as rain and fog. However, lighthouses also help to mark the coast by day.
A system developed by the Lighthouse Board (est. 1852 by U.S. Congress) designated individual lighthouses as "day marks" by the use of painted patterns. Unique patterns painted on lighthouses enable sailors to recognize them as markers for particular locations during the day. Although many lighthouses are painted with similar patterns, they are far enough apart to prevent them from being confused with one another.
Some lighthouses have simple bands of color, others are painted with spiraling lines and still others are painted one solid color. The most common colors used to paint lighthouses are white, black and red. A few lighthouses notable for their markings include: