Thanks for the additional info Tomoko.
I would have guessed that the tank is only 300 to 400 gallons -- not that big for all that it has in it. It is the only reef tank they've got, but the entire Ocean Hall exhibit is truly fabulous.
The clam that shows up well in Tomoko's pics and video is gigantic -- 3 or 4 times larger than my Derasa which many of you have seen. I couldn't get close to it because there were about ten little kids pressed up against the glass along the bottom of the tank while I was taking my pics.
As far as visiting D.C. goes, there's a tremendous amount to see, and most all of it is free. Besides all the the memorials, monuments and government buildings, the Smithsonian exhibits alone would take days to walk through if you were just going to glance at everything. We enjoyed the Museum of Natural History, the Impressionists paintings in the national gallery of art, and several of the exhibitions in the newly re-opened Museum of American History.
fwiw,
Mariner