A monument is erected to commemorate the arrival of the first Japanese naval ship Kanrin Maru in San Francisco Bay on 17 March 1860.

A commemorative plaque, or simply plaque, or in other places referred to as a historical marker or historic plaque, is a plate of metal, ceramic, stone, wood, or other material, typically attached to a wall, stone, or other vertical surface, and bearing text or an image in relief, or both, to commemorate one or more persons, an event, a former use of the place, or some other thing.[from wikipedia]

Yerba Buena became San Francisco, January 30, 1847.