The shipwreck graveyard at Land's End, CA

Taken from the NPS site page.

One thing I never fully realized as a kid while playing on the beaches of San Francisco's western shore is just how many shipwreck debris I was playing in on a regular basis. 

For hundreds of years, San Francisco has been quite possibly the largest port on the western coast and with good reason. However, the frequent heavy fog, massive tidal forces, combined with large swaths of jagged rock just under the waterline outside of the bay, has made the land between Land’s End and the Marin Headlands a hot spot for shipwrecks and has claimed over 300 ships.

The sheer number of wreck is difficult to document here, so instead I'll link to the National Parks Service site that has a page with a short listing of about eight of the most notable ones that you can read about and is well worth the visit: https://www.nps.gov/goga/learn/historyculture/vestiges-shipwrecks.htm