Section

Geography

Faults, straits, and summits, and the deep time that shaped them.

The Golden Gate strait

The Bay's only door to the ocean wasn't always here. A fault opened it, and the sea came through.

The San Andreas FaultThe boundary between two plates runs just off San Francisco's coast.
Mount TamalpaisThe peak above Marin, once climbed by the crookedest railroad in the world.
Angel IslandThe Bay's largest island, and the immigration station on its shore.