Die Glocke first appears in Witkowski's 2000 Polish-language book Prawda o Wunderwaffe, sourced to alleged transcripts of an interrogation of SS General Jakob Sporrenberg, shown to Witkowski in 1997 by an unnamed contact. Nick Cook's The Hunt for Zero Point, 2001, carried it to English readers; aerospace historians such as David Myhra doubt the device existed. No document, part, or witness beyond that chain has ever surfaced.
The legend needed a villain with authority and no death certificate, and found Hans Kammler, the SS general who ran secret-weapons construction and vanished in May 1945. His unmarked exit lets the story assign him the Bell, the saucers, and a defection, because a corpse with a grave could not carry that much plot. The concrete Henge ruin at Ludwikowice became the Bell's launch facility by caption, not by record.
National Geographic's reviewer noted the Bell has a following similar to science-fiction fandom, which is precisely what it is: a shared fictional universe with footnotes. Its persistence shows how a wonder weapon works narratively: the less documented the object, the more documentaries it generates.
If a legend's entire documentary basis is one unverifiable notebook, is the legend history or literature?