Levi Strauss and Jacob Davis invented denim jeans in San Francisco for the Gold Rush miners who needed durable yet comfortable clothing.

In the wake of the 1929 stock market crash, thousands of banks went out of business across the U.S., but not a single San Francisco-based bank failed. Indeed, it was at the height of the Great Depression that San Francisco undertook two great civil engineering projects, simultaneously constructing the San Francisco-Oakland Bay Bridge and the Golden Gate Bridge, completing them in 1936 and 1937, respectively.

The Barbary Coast was a red-light district during the second half of the 19th and early 20th centuries in San Francisco that featured dance halls, concert saloons, bars, jazz clubs, variety shows, and brothels. Its former location now is overlapped by Chinatown, North Beach, and Jackson Square.

At 5:12 am on April 18, 1906, a major earthquake struck San Francisco and northern California. As buildings collapsed from the shaking, ruptured gas lines ignited fires that spread across the city and burned out of control for several days. "Not in history has a modern imperial city been so completely destroyed," Jack London wrote afterwards. "San Francisco is gone."

The initial toll for the bridge was 50 cents each way--roughly equivalent to an $18.00 roundtrip today--a hefty price to pay in the midst of the Great Depression. Today, Golden Gate Bridge tolls are collected in one direction only, heading southbound into the city of San Francisco.

In 1977, Harvey Milk became the first openly gay person elected to a public office in California. He served almost eleven months on the San Francisco Board of Supervisors and sponsored a bill to ban discrimination in public accommodations, housing, and employment on the basis of sexual orientation. The Supervisors passed the bill by a vote of 11-1, and it was signed into law by Mayor George Moscone. On November 27, 1978, Milk and Moscone were both assassinated by Dan White, a disgruntled city supervisor. Despite his short career in politics, Milk became an icon in San Francisco and a martyr in the gay community.

After the exposition, Treasure Island was slated to become a second airport for San Francisco, but the U.S. Navy offered to trade their Mills Field on the peninsula as an airport site (now SFO) for ownership of the island.

In 1867, San Francisco instituted America's first "ugly law," which prohibited "any person, who is diseased, maimed, mutilated or deformed in any way, so as to be an unsightly or disgusting object, to expose himself or herself to public view." Violators were hit with a $25 fine (about $460 today), 25 days in jail or both.

The "Zebra" murders were a string of racially motivated murders perpetrated by a group who called themselves the "Death Angels" in San Francisco from October 1973 to April 1974. They killed at least fifteen people and wounded eight others, though some authorities believe they may have killed as many as 73 victims. Police gave the case the name "Zebra" after the special police radio band they assigned to the investigation.

The city of San Francisco is geographically constrained to the tip of a peninsula, measuring approximately seven miles wide by seven miles long. But for years, when San Franciscans wanted more real estate, they simply made more land. Many communities, including Marina, Mission Bay, and Hunters Point, are built on top of landfills.