The “old” Point Loma lighthouse was active from November 15, 1855 until March 23, 1891 (36 years),  warning ships entering San Diego Bay.  However, its location high atop Point Loma resulted in its beam often being obscured by fog and clouds such that a “new” lighthouse was built down at sea level.  The old lighthouse has been restored and offers great displays including a five-foot tall 3rd order Fresnel lens, the best available at that time.

Links:   NPS