In Conqueror of Shamballa, Edward walks into the movie set in Berlin UFA Film Studios. The movie in question is Siegfried, Part 1 of Fritz Lang's saga Die Nibelungen (1924). Several scenes from the silent film were reproduced accurately:
-The Dragon and the pool, where Siegfried will bathe naked in the creature's blood.
-Brunnhild's (Hanna Ralph) entry to the Nibelungen palace, Seigfried's (Paul Richter) pact with King Gunther (Theodor Loos) with the one-eyed Hagen Tronje (Hans Adalbert Schlettow) and Kreimhild (Margaret Schoen) looking on.
-An array of the Nibelungen army, with a close-up of Kreimhild (looking far more feminine here than she does in live action).
-The matte shot of Brunnhild's mountaintop palace with a rainbow, where Edward and Fritz Lang lunch.

This point is rarely mentioned in this forum. Did anyone actually watch Siegfried? Did anyone try to see Fritz Lang's other films like Doctor Mabuse (1922), Metropolis (1926), M (1931), Testament of Doctor Mabuse (1932), Fury (1936), Scarlet Street (1945), and The Big Heat (1953).
Incidentally, Lang assisted in a 1916 serial called Homunculus, about a man-made monster taking over the German government. Perhaps the creators knew about this...

Here's an interesting quote from a discussion poster named Phil Yff.
"FMA – the series and the movie – contains numerous allusions to German philosophy. The historical Lang was one of the standard bearers of German expressionism. One of the hallmarks of German expressionism is the heavy use of symbolism to add layers of meaning to a film by evoking memories and thoughts to cultural heritage and traditions. FMA, itself, makes heavy use of archetypal symbols which adds to its profundity."