Marching by (Extrapolated) Numbers
Charlie Martin -- a computer scientist with extensive intelligence experience -- emails from his secret bunker near Boulder, CO:
I did a back-of-envelope based on the photos and reports. A pretty dense crowd is about 1.8 people per square meter, and the National Mall alone is about 125 hectares, 1.25 million square meters. So that would be 2.3 million people.
Given the report from Steve of an actual literal count of 450K early on, I think the 2 million number is *very* plausible.
Knowing Charlie like I do, I'm inclined to trust his guestimates more than most people's "facts."
Which in this case... whoa.