What is San Francisco didn’t used to be San Francisco. We’re a small city; 7 miles by 7 miles (give or take.) The story of San Francisco always involves land: how to use what little we have, and how to get more of it.
This map shows the original shoreline. Soon after the Gold Rush in 1849, Yerba Buena Cove got filled in with abandoned ships and became the Financial District. The Marina lies on top of debris from the 1906 Earthquake and Fire.
So when you walk on the two flattest parts of San Francisco, you’re walking over the 2 major events in San Francisco history.