In October 1941, FBI director J. Edgar Hoover received a strange bit of war intelligence in a classified document, the Appendix details. The correspondence warned that a secret German airbase had gone up deep in the heart of the Amazon rainforest. In a note quickly sent to the Assistant Secretary of State, Hoover warns:

“As of possible interest to you, information has been received from a reliable confidential source that there are rumors current in Brazil as to a German air base, reported to exist in the Rio Negro district of the upper Amazon. Additional information will be furnished you concerning this when it is received.”

Particularly concerned about an attack on the Panama Canal, the FBI began collaborating with Brazil’s secret police.

In December, another worrying message came through. The suspected culprits behind the scheme were a colony of German monks. The FBI wondered if these forest-dwelling worshippers may be preparing for a secret base for the Luftwaffe, the airborne arm of the German military.

The following July, Hoover received another piece of evidence. Large amounts of fuel had been spotted traveling upriver in Bolivia. Given that gasoline was very much in short supply given the world war, the numerous canisters raised suspicions. The FBI worried that the fuel could be headed to the secret jungle airbase, still yet to be discovered.

In the end, though, military leaders concluded that stockpiling enough supplies deep within the jungle would not be possible. The would-be Nazi monks were left to live their own quiet, solitary lives in nature.

Here’s the monk memorandum, for closer examination:

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