I spent the day today at the American Museum of Natural History, which I hadn't seen in some 15 years. It still beats the pants off the Smithsonian. Many of the exhibit halls have been renovated, most notably the Hall of Ocean Life, and the museum as a whole has been rearranged to better represent modern evolutionary theory. The new Hall of Biodiversity is excellent; I particularly liked they way they juxtaposed descriptions of serious ecological problems with inspirational quotes... it sounds cheesy, but it really worked.
The new wing on the museum is the Rose Center for Earth and Space, containing an enormous sphere. The upper part of the sphere is a state-of-the-art digital planetarium, where I watched a show about the case for extraterrestrial life. You exit the planetarium on a catwalk whose displays use the sphere itself to teach about the scale of things: if the sphere were the sun, the Earth would be a basketball; if it were a hydrogen atom, a proton would be the size of a pinhead, etc. Then there's another theater in the lower half of the sphere showing a short film about the Big Bang, and you exit onto another catwalk that chronicles the history of the universe, 1 foot = 50 million years. At that scale, all of human history is the width of a hair at the end of the catwalk!
You may have noticed that my tour map has some blue dots described as "Great Story Sites." (Though you may not have, since the map loses some detail each time I edit it!) This museum is the first such site I've made a point of visiting, and I must say it qualifies... between the story of the universe and the story of evolution and the stories of human cultures and agriculture, there are a lot of Great Stories being told there, and more than anyone can absorb in a day!