I have been living in DC for eight months and have seen most of the highlights.
Yohannes' tour was extremely educational. He seems to know everything there is to know about every building, monument, statue and embassy in the District. His knowledge of American history amazed me. I didn't want the tour to end. I get the feeling I could take a tour with him again and he would have a full days' worth of completely different sights and information to share with me.