The central public space is great for people-watching and street performers are often showing off nearby. You can have a bit to eat and a cup of coffee at the small cafe, or young girls might enjoy afternoon tea at one of the many upscale hotels nearby.
During the summer, you can enjoy live music and other activities in the park and there's an outdoor ice-skating rink in November and December. Not far away on Market Street, the San Francisco Shopping Center has some unusual, spiral escalators that kids like to ride. And for the artsy kinda kid, the theatre district is right next door.
Pros and ConsUnion Square is fun to see, lively and close to both Chinatown and the cable car line. Of all the spots in San Francisco, it feels most citi-fied.
Union Square is also the city's most expensive shopping area and many of the stores are nationwide chains, but it's also home to some places that are uniquely San Francisco, like Gump's department store and multistory fabric emporium Britex.
On the downside, parking is exasperating and expensive and if you don't want to shop or watch people, you'll be done with it in just a few minutes.
More about Union SquareUse the Union Square guide to get more ideas and find out all the places of note.
Take a photo tour to see what it's like. There's a map, too.