On April 18, 1906, an earthquake with an estimated 8.3 magnitude on the Richter scale hit San Francisco, which at the time was the biggest city on the West Coast.
San Francisco was a bustling, progressive port town and cultural center with a population of over 400,000, a booming economy, public transportation in the form of its famous cable cars and some of the most grand architecture of the day. The cosmopolitan city was world-renowned. By comparison, the cities of Los Angeles, Seattle, and Portland were in their infancy.
Life was good in San Francisco on April 17, 1906, the day before the earthquake. The lavish mansions of the "Big Four"—wealthy railroad magnates Charles Crocker, Leland Stanford, Mark Hopkins, and Collis Huntington—overlooked the city from atop the now-famous Nob Hill.
That evening, famed operatic tenor Enrico Caruso, who has been called the Elvis Presley of the day, performed in Carmen at San Francisco's Grand Opera House. The luxurious new Fairmont Hotel was scheduled to open on Nob Hill the next day. San Francisco had arrived.
Little did the people of San Francisco know that, within hours, their magnificent city would be leveled to the ground. The history and science surrounding the 1906 San Francisco earthquake is incredible. There were earthquakes before, and there have been earthquakes since, but nothing to date has lived up to this earthquake, not only in magnitude, but because of the context of the times in which it occurred.

Seismologists agree that a quake of that magnitude will hit only once every two hundred years. At the turn of the last century, the people of San Francisco were caught completely unaware and found themselves ill-prepared to deal with such a disaster.
I'm a history enthusiast, so I dove into researching the earthquake with enthusiasm and then drove my family and friends crazy with statistics. "Did you know that 225,000 people were left homeless by the earthquake, more than half the city's population of 400,000 at the time?" (Yes, I'm beginning to sound exactly like the kid from Jerry Maguire.)

When my daughter Melissa was going to college in San Francisco in 2006, she had the opportunity to observe the earthquake’s centennial by going to the Little Shamrock (807 Lincoln Way, San Francisco, (415) 661-0060) for the 5:12 a.m. festivities. The Little Shamrock is an Irish pub in the Sunset District. It survived the earthquake, and its employees helped feed San Francisco's displaced citizens. When the earthquake hit at 5:12 a.m. on April 18, 1906, the pub's grandfather clock was knocked off the wall. Its hands have been stuck at 5:12 a.m. ever since.
If you're interested in learning more about the 1906 earthquake, you can read my post on The Great San Francisco Earthquake and Fire of 1906. As with most subjects, the most significant thing I learned is that there is so much more to learn. There's a lot more information out there on the internet. Also, the Great San Francisco Earthquake was the first large-scale disaster occurring in the day of ready photography, so there are lots of pictures available, as well as seismic data, newspaper articles, and first-hand accounts.
Note: The Little Shamrock is the second oldest bar in San Francisco. The oldest is the Old Ship Saloon on the Embarcadero, established in 1851, and so named because it’s made from a ship’s hull that ran aground during a storm off Alcatraz Island.