I remember this so vividly. I walked the length of the Mall, stood on the west front steps of the Capitol (which you can no longer do) and stared out onto a virtual sea of candles flickering on the Mall. This photo is a good representation of what I saw that night on September 12th, the day after the tragic events in New York, Washington, and Pennsylvania. I wrote another post about this some time ago.
Source: The Daily Signal