Purim is a holiday celebration like no other
24. Wave Organ
The Marina's Exploratorium is a fun science museum - but it costs you $14 (although it is free on the first Wednesday of every month). An always free, worthy side project is the Wave Organ, a sound system of PVC tubes and concrete pipes capped with found marble from an old cemetery built right into the tip of the Marina Boat Harbor jetty. Tones shift depending on waves, winds and tide, sounding alternately like spooky breathing on a phone and the nervous humming of a dinnertime line chef.
25. Westin St Francis' glass elevators
It is cheating – and we are not literally suggesting you do this – but let us just say we have “heard” that you can go into the hotel, walk past the front desk as if you are a guest and take the glass-walled, tower elevators up 32 stories for drop-dead vistas over Union Square and San Francisco.