Construction began on the lighthouse in early 1854 and was completed in November 1855. By late summer 1854, the work was done. More than a year passed before the lighting apparatus - a five-foot-tall 3rd order Fresnel lens, the best available technology - arrived from France and was installed. At dusk on November 15, 1855, the keeper climbed the winding stairs and lit the oil lamp for the first time. In clear weather its light was visible at sea for 25 miles. For the next 36 years, except on foggy nights, it welcomed sailors to San Diego harbor. However, the lighthouse's location on top of a 400-foot cliff meant that fog and low clouds often obscured the light from the view of ships.