After Mt. Vernon, we all took an hour break at a mall for dinner and shopping. Then we moved on the DC Monuments at Night feature of the day. I really think that DC was designed to see at night. Everything looks so much more... etheral. Long-lasting. Dignified. Closer to the spirit of what L'Enfant and the Founding Fathers thought of America and DC.
If you ever go to DC, take a tour at night or just walk around. It's much better then.
Pictures next, to prove my point.