Every year on April 18, residents of San Francisco gather around Lotta’s fountain to commemorate the date of the 1906 earthquake that almost removed San Francisco from the map: what did not fall to the ground was burned by a huge fire following the earthquake.
More information: http://blog.sevenponds.com/something-special/%E2%80%A8%E2%80%A8lottas-fountain-and-the-1906-san-francisco-earthquake