Perched on a cliff on the central California coast, 50 miles south of San Francisco, the 115-foot Pigeon Point Lighthouse, one of the tallest lighthouses in America, has been guiding mariners since 1872. Its five-wick lard oil lamp, and first-order Fresnel lens, comprised of 1,008 prisms, was first lit at sunset, November 15, 1872. The lens stands 16 feet tall, 6 feet in diameter, and weighs 8,000 pounds. It sits in a lantern room that had been constructed at the Lighthouse Service's general depot in New York before being shipped around the Horn. Although the original Fresnel lens is no longer in use, the lighthouse is still an active U.S. Coast Guard aid to navigation using a 24 inch Aero Beacon. The coastal areas surrounding Pigeon Point Light Station are rich with life. Marine mammals, such as seals and whales, can be seen regularly from shore as they pass by beyond the surf. The intertidal zone along this part of the coast, particularly in the rocky reefs that flank the light station, contains a diverse and numerous variety of plant and animal life. From the boardwalk behind the fog signal building, watch for gray whales on their annual migration between January and April. Walk through the tide pool area, 100 yards north of Pigeon Point, or through the amazing 1,000-year-old redwoods nearby. Explore Pescadero Marsh, the feeding and nesting place for more than 150 species of birds, and Año Nuevo State Natural Reserve, the breeding site of northern elephant seals. Be prepared for unpredictable weather. Rain may occur between November and March, and even summer brings chilly fog, particularly in the mornings. Stiff northwest winds can develop anytime, so dress in layers. The day-use area is open from 8am to sunset.