San Francisco was founded by Spanish missionaries in 1776 and it remained a small town for over 70 years. As late as 1848 it had a population of a mere 1,000 or so.
But the California Gold Rush, which began that year, sparked a population spurt, while its coastal location eventually turned San Francisco into one of the most important ports in America. By the turn of the century, its population had hit 400,000.
However, the city’s location proved a double-edged sword: it also lies on the northern section of the San Andreas Fault, where the Pacific and the North American tectonic plates collide.
In 1906, a major earthquake struck California and was felt as far away as the adjoining state of Nevada. The epicentre of the quake was just two miles outside the city, leaving San Francisco particularly badly hit.
The initial shock destroyed large numbers of buildings and caused fires that spread rapidly through the city. Up to 75% of the population was left homeless. The official death toll was put at 375 casualties, but historians now believe the real number was nearly ten times greater.
The city was rapidly rebuilt, thanks to the generous lending policies of the Bank of Italy (now Bank of America Merrill Lynch), which had been founded in San Francisco. Indeed, the refugee camps established to provide temporary accommodation were all closed down by 1908.
However, the huge insurance costs (estimated at $6.5bn in inflation-adjusted dollars) weakened many insurance companies, and were blamed for the Panic of 1907-1908, which saw the stock market lose half its value.