When tourists visit San Francisco’s Ferry Building and wander around the Financial District, do they know that part of the City was once underwater? Amidst the towers was once a busy harbor. During the Gold Rush, crews that ran off to the Sierra Nevada abandoned their ships. Those ships sank into the mudflats as wharves and docks grew around them. Eventually the harbor was filled in and the coastline expanded out into the bay. Imagine Justin Herman Plaza was once a tidal flat filling with seawater twice a day. While Time Travel Photos are about both the past and the present, this one might also be about the future as sea levels rise.