Fog has a long and colorful history. First seen by white men in the San Francisco Bay Area in the 18th century, it has since spread around the globe. In San Francisco, fog has played a major role in a number of major historical developments, and is one of the City's signature features.

1769 Spanish conquistadors of the de Portola expedition reach Montara Ridge above San Francisco Bay, becoming the first white men to view fog.

1886 HMS FogWatch departs from Great Britain with the mission of measuring fog levels around the world.

1889 A group of explorers led by Scottish eccentric Conor MacCormack disappear in the Sunset District while trying to become the first white men to cross the sand dunes on the western edge of the City. View related story.

1898 HMS FogWatch arrives in San Francisco Bay and lays anchor.

1906 A rolling fog bank is credited with putting out fires caused by the 1906 earthquake, saving the western half of the City from devastation.

1901 The steamship City of Rio de Janeiro becomes lost in the fog and sinks just under the Golden Gate Bridge, killing nearly 130 people. The wreck of the ship, still undiscovered, reportedly contains over $2 million in silver bars.

1941 A Japanese commando party hoping to raid the western shore of San Francisco encounters heavy fog and instead lands on the Farallon Islands, where they are smothered to death in guano deposited by angry seagulls.

1950 First test of fog as a potential weapon of war. U.S. Army sprays serratia marcesens and other bacterial agents into fog from ship offshore to test potential impact of biological attack on San Francisco. Although the agents were thought to be harmless, at least one San Francisco resident falls ill and dies as a result.

1968 Newly arrived hippies camping in Golden Gate Park are forced to huddle together for warmth as bone-chilling fog banks roll through the Haight-Ashbury District. What later transpires comes to be known as the Summer of Love.

1972 Fogg-Bottom Museum of Beer Photography founded in San Francisco.

1974 Fog plays a crucial role in the Symbionese Liberation Army's robbery of a Hibernia Bank branch in the Sunset District. The sudden arrival of a thick fog bank enables Patty Hearst and other SLA members to escape from pursuers.

2001 FogWatch.com goes live, providing San Francisco residents with late-breaking news and information about fog.