I just finished reading the chapter on Washington, D.C. (I am hoping for a PBS showing of the series in the USA at some point) - and contrary to the comment that the Capitol Steps are "... becoming nearly as much of a Washington institution as Grant's Tomb or the Lincoln Memorial..."
I lived across the street from Grant's Tomb for several years, and can attest to its location in New York City. I used to practice Tai Ji on the large, flat expanse in front of the memorial - the security guards thought I was nuts on snowy winter mornings.
Funny thing is, when my mother visited me there, she (a native Californian, now living in Oregon) was shocked to find that Grant's Tomb was not in Washington D.C!! So, Stephen, you are in good company. Wrong, but in good company.
Thanks for making me smile and think of my Mom.