The Old Castle in Ingolstadt, where Hagbard Celine hosts a dinner featuring lots of good German beer.
(This week: "Are you a turtle?" Lady Velkor asks again, page 605, to page 617, "Just then, Joe distinctly heard a rooster crow.")
While Lake Totenkopf is fictional, Ingolstadt is a real German city and is indeed the birthplace of Adam Weishaupt, the founder of the Bavarian Illuminati. Weishaupt was a professor of the University of Ingolstadt. Victor Frankenstein, in Mary Shelley's novel, attended the university. There's apparently no great lake by the city, which is in fact on the Danube, thus putting it on the frontier of the Roman Empire. The Liebfrauenmünster and Maria de Victoria churches, mentioned on page 606 under slightly different names, are real places.
The town hall in Ingolstadt.
"It depicted the Holy Roman Emperor Henry IV barefoot in the snow at Canossa," page 608. This is a reference to famous incident in which the emperor stood in the snow, begging Pope Gregory VII to forgive him. The pope, although a significant figure, is not in fact Gregory the Great, so the authors get that bit wrong.
"Mal, baby," Joe cried, page 611. Malaclypse the Elder, who we encountered in Chicago. See the Illuminatus section of this article.
Just then, Joe distinctly heard a rooster crow, page 617. Hagbard's oddball reenactment of the Last Supper seems to be conflated with Peter's denial.
I am in the middle of working 10 days in a row, so I am afraid this posting will be a bit shorter than I would like.
(Next week: "Cars, except for official cars and the vehicles of the performers," page 617, to page 627, "Come over here and get the energies going with me.")