6. The City by the Bay may be best known for its sourdough bread and Victorian architecture, but at the holidays the shops go all out to turn the town into a winter wonderland. Start your adventure in the heart of the holiday shopping district at Union Square. If you're an animal lover, don't miss the seasonal Pet Adoption Windows at the Macy's department store. They're hosted in partnership with the SPCA, and the event puts cuddly kittens and cute puppies on comfortable cushions in holiday-themed windows, where they wait for some good Samaritan to stop by, fall in love and adopt them. In 2007, more than 200 pets found good homes. Even if you don't plan on adding a new member to your family, the seven-story department store sells a diversity of goods, from cosmetics to children's clothing. Macy's: (415) 397-3333.