Helen and I visited the California Academy of Sciences in Golden Gate Park in San Francisco last weekend. This museum-and-research institution was founded over 150 years ago, and recently re-opened in new digs following its partial destruction in the 1989 Loma Prieta earthquake.
The new Academy is amazing. I don't know any better word to use to describe it. Check out the Web site (see link above) and see for yourself a little about what it's like—but you won't really understand until you can visit.
I could ramble on for pages. To avoid that, I'll just briefly describe the most amazing feature. This is the Rain Forest, contained inside a glass sphere 90 feet in diameter. The sphere contains maybe 10 feet of water at the bottom, in which hundreds of fish swim (and some of them are huge). From ground level, trees go up four stories, and are filled with birds and butterflies. Side exhibits include a bat cave (we watched a curator hand-feeding little bits of fruit to the hanging bats) and a large leaf-cutter ant farm. You enter at ground level, and follow a ramp that spirals up the inside of the dome. At each level there's something different to see: the fish, the plants, the birds, and the omnipresent butterflies that float around you. From the top, a glass elevator takes you down under the water for a close-up view of the underwater life. It is stunning; I think I could spend all day there, just in that one dome.
And there's more: the Morrison Planetarium (which we missed, for lack of time), the Steinhart Aquarium (still reigned over by the resident albino alligator), and even the roof which is covered with earth and planted with low-maintenance native groundcover.
Go, see it, it's wonderful. But don't drive there. We had an absolutely terrible time finding parking, and the traffic jams were horrific. Take BART to the city, then grab one of the buses that will take you straight to the Academy's door. Oh, and buy your tickets ahead of time on the Web, it will save you time getting in.