All due credit goes to Freeper Dan Day for this compilation...EXCELLENT!
The top two photos are from the Million Mom March, May 14th, 2000
 
The reverse shot from ground level for Note 1. Note 1.
Note 2 Note 3

 

NOTE 1.--Note that the crowd stops at the uppermost white "tent", and green grass (unobscured by people) and a white sidewalk are clearly visible at the top of the picture. The stage for the MMM is at the lower part of the picture -- the photo shows the ENTIRE crowd, and it by no means extends from "one end of the mall to the other".

NOTE 2.--This is an aerial photo of the 1997 "Promise Keepers" march, which official (not just rally-originated) estimates put at 300 thousand, for real.

NOTE 3.--The green line marks the position of the sidewalk that appears in the upper portion of the MMM photo -- you can see the breaks in the trees where it enters and leaves the mall, and bits of it on the right and left sides.
The yellow outline therefore marks the area that the MMM crowd would have filled if viewed from the same angle as this Promise-Keepers aerial photo.