Zazzle Bay-to-Breakers 12K

If you truly want to understand the City on the Bay, this is best—if the most grueling—way to do it. San Francisco held its first race (almost a half-marathon) in 1912, and they’ve kept the course in tact—traveling from the northeast end of downtown to the west end of the city. The more manageable distance also appeals to a wider swath of the city—in 1986, the race set a world record, attracting 110,000 runners.