The Secrets of Masonic Washington: A Guidebook to Signs, Symbols, and Ceremonies at the Origin of America's Capital by James Wasserman is one of copious books that examine the manifestations of masonic and esoteric symbology in Washington, D.C. However, the book takes a fresh approach that makes it more interesting and practical than most of its genre.
Written in the style of a walking tour, Wasserman's book is filled with maps and beautiful photographs. The discussions are clear, cogent, and just the right length for reading while you're standing in the location being described, but the photography makes the book appropriate for arm chair tourists too.
Unlike many authors in this subject area, Wasserman is careful not to impart Freemasonry on persons and objects where history is unclear on their actual relationship with the fraternal order. This refreshing approach also permits Wasserman to offer observations about memorials and architecture that feature esoteric symbolism that is not directly tied to the Order. Thus he avoids becoming too much of a Masonic booster, and makes the book more interesting across the board. For example, a lovely photo of the Second Division Memorial includes a discussion of its central design element which echoes the Ace of Swords from the Tarot deck.
Overall it's a high quality book, both in content and production, and it's inexpensive price at Amazon makes for an easy buying decision. If this topic interests you, I think you'll enjoy it too.