Long Point Light

Long Point Light Station is an historic lighthouse at the northeast tip of Long Point in Provincetown, Massachusetts. As a navigational aid, it marks the southwest edge of the entrance to Provincetown Harbor. The United States Coast Guard Light List describes it simply as a "white square tower". The light it casts is green, occulting every 4 seconds, and, at a focal height of 35.5 feet (10.8 m) above mean sea level, has a visible range of 8 nautical miles (15 km; 9.2 mi). When the weather affords low-visibility, one can hear the station's fog horn – sounding a single blast for two seconds, and repeating every 15 seconds – as it seems to call out for (and answer calls from) its nearly-identical closest neighbor, the Wood End Light.

• http://en.wikipedia.org/wiki/Long Point Light