According to the passage, what happened in 1848?

Good afternoon, ladies and gentlemen. From here we can enjoy one of the most beautiful views of San Francisco. As you can see, the city rests on hills.
   The first permanent settlement was made at this site in 1776. For thirteen years it had a population of less than 100. But in 1848, with the discovery of gold, the population grew to ten thousand. At the same year the city got its new name San Francisco.
   By 1862 telephone communication linked San Francisco with eastern cities, and by 1869 the first railroad connected the Pacific coast with the Atlantic seaboard. Today San Francisco has a population of almost three million.
   Now please look to your right. Here you’ll be able to see the east section of the Golden Gate Bridge. The bridge is more than one mile long.  It was completed in 1937 at a cost of thirty-two million dollars and is still one of largest suspension bridges in the world.