We also have a pretty strong historical record of how the Bermuda Triangle story came about. It was invented (with roots in an article back in 1950 and certainly by the time of Berlitz' book in 1974.)
One of the other early adherents was one Ivan T Sanderson, who in one of his books (which I have, but my library is a real mess) had a Chapter "Vile Vortices" devoted to the Bermuda Triangle, and supposedly seven other "losenge" (I think) shaped areas in equidistant points around the earth, including the almost as famous one near Japan - The Devils Sea. Sanderson believed in all things woo, including Bigfoot.
This book did precede Berlitz, and offered about the same level of evidence.
I have about seven boooks (again, somewhere) on the Bermuda Triangle, and when comparing all the True Believer book items, remain staggered that the major detail of "what actually happened" never agrees from book to book, and grows in the telling in later books.
I am amazed that anybody who read Kusche's first book on the subject which was fully annotated with references to ALL of his source material, which can be followed up by anybody who really wants to know whether he was lying or not, can even believe that the Bermuda Triangle has any mystery involved.
ETA It's a bit like coming across
Chariots of the Gods in a second hand book shop, and thinking wow! Von Danicken is onto something here.
Norm