Big model related:

Back in the 80s, when I lived near Sausalito, one free Saturday I visited the US Army Corps of Engineers Bay Model. It is a huge and incredible scale model of the hydrology of the whole Bay Area and a part of the Sacramento-San Joaquin river delta. It is larger than a football field. The day I visited there was almost no one else there and I got a leisurely two hour tour.

I have read that, today, it is very popular with long lines.

https://en.wikipedia.org/wiki/U.S._Army_Corps_of_Engineers_B...