Among the movie's many revelations is the fact -- I'm taking the factuality on faith -- that the Vatican library's most treasured manuscripts are stored in sealed chambers under a partial vacuum.

WSJ: Plot's Knots Bedevil 'Angels & Demons'

When the Catholic Habsburgs defeated the Protestant Palatine Elector Frederick V in 1620, they reduced Heidelberg Castle to ruins and carried off the contents of the library as spoils of war - by this time totalling over 3, 500 manuscripts and 13, 000 printed works - to the Vatican Library in Rome where they remain to this day.

BBC: A Point of View: Why didn't Harry Potter just use Google?

America's Library of Congress used the web to create an electronic version of an exhibition of manuscripts from the Vatican, letting an electronic visitor wander from link to link, looking at pictures and reading about them rather as a real visitor might stroll from corridor to corridor.

ECONOMIST: From the archive