I was sitting in the lobby of the Hyatt Regency Embarcadero, San Francisco when the sun's diurnal track across the sky allowed it to quite suddenly shine directly into the vast, towering space, illuminating it beautifully. While very long, the roof skylight isn't very wide so the effect only lasted about 10 minutes but it was cool! I was fortunate to have been in the right place at the right time with a camera and tripod.