"A crowd estimated at 250,000" in St.Peters Square witnessed the Pope make Mother Teresa a saint,
said the news media. How accurate was this figure? I've wondered about this kind of
reporting since discovering that in Washington, D.C., where I live, protest marches were typically
reported as being about twice as large as they actually were.
A photograph of the beatification ceremony published in the Washington Post
provided an unusual opportunity to confirm the reported number, first because of the level of
detail it shows, and second because maps of the area are available to use in correcting
for the foreshortening distortion in the picture. I conclude that there are about
105,000 people shown in the photograph, or less than one half the number handed down to us
by the press. Below, I show step by step how I arrived at that figure.
Scanned-in photo from the print edition of the Washington Post, Oct. 20, 2003.
(The counting for the estimate was made using the print version.)
Full-resolution image .
A section of the audience within the white rectangle is seated in an array of
about 20 columns across and 40 rows deep. (
Enlarged detail .
If we conservatively use 1000 as the number of people within the rectangle...
...and multiply by ten, the number of similar sections within the foreground area
bounded by the white line in this photo...
...then there appears to be 10,000 people in an area that we can relate to the total
area of St. Peter's Square using this diagram. The area is within the black trapezoid. Using a
image, some tracing paper and graph paper, we can determine that it is about one eighth...
...of the area within the white line in this image. Therefore there are about 80,000 people
within St. Pater's Square. It remains to determine the area in the rear beyond the square.
Assuming that the windows in the side buildings are spaced the same as those in the building
going across, we can estimate that it has an area large enough to contain an additional 25,000
people. Therefore this photo shows a crowd of about 105,000.