Easy one.

Photo via Google Maps.
Congrats to Tony Turner.
Answer below the fold.
This is part of the Library of Congress.
Library of Congress.
Posted by Tony Turner on March 13, 2008 at 0741 hrsActually, to be more percise…
The Jefferson Building of the Library of Congress. The Library is in three buildings (Madison and Adams are the others) it’s gotten so big. It once took me an hour for them to get a book for me.
Posted by on March 13, 2008 at 0809 hrs