Koret Children's Quarter (San Francisco, Calif.)
Warning: Adults may not enter the playground unless accompanied by a child. If that sign doesn't say it all … well, it says most of it. Koret Children's Quarter in San Francisco is one of the best urban playgrounds ever. Its concrete slide (you slide down on a piece of cardboard) and 3-dimensional rope climbing structure up its cool factor, as does its restored 1912 carousel. The playground is designed with areas for both little and big kids, and has swings, slides, monkey bars, a rope bridge, sand pits and a wave area.
Koret Children's Quarter is considered one of America's oldest playgrounds. It was renovated in 2007.