Chatham Light, near the elbow of Cape Cod in Chatham, Massachusetts, began in 1808 as the Cape’s second light station and originally operated as twin lights to aid navigation and distinguish it from Highland Light. Its towers were repeatedly rebuilt and relocated as erosion and shifting channels altered the shoreline, evolving from movable wooden towers to brick structures and eventually to the single tower known today after one tower was moved in 1923 to become Nauset Light. The station also changed with advancing technology, from oil lamps and Fresnel lenses to electric power and automation, while the site remains active through U.S. Coast Guard operations.