Hey, history lovers. I'm Mike Rosenwald with Retropod, a show about the past, rediscovered.

So this is a crazy one. In late 2006, a team of power company workers was trudging through a ticket of

government land in southwest Washington, D.C. when they spotted something odd in a ditch. There,

settled in the grass, was a rectangular slab of granite.

They looked closer, and an inscription came into focus. What they saw astonished them. It was a

memorial, in honor of Nazi spies, on U.S. government property. The engraving read in memory of agents of the German Abvir, executed August 8, 1942.

Below that were six names, and below those was another cryptic one, donated by the NSWPP.

What was a memorial to Nazi spies doing on government property?

A man named Jim Rosenstock is the one who unraveled the mystery.

Back then, he was a national park service worker and a big-time history buff.

When he heard about the stone, he started doing some research into the

stone's origins and found an incredible tale, complete with World War II espionage, nationwide

panic, a mass electrocution, and even J. Edgar Hoover. According to Rosenstock, at the start

of World War II, Adolf Hitler had been determined to show the world just how susceptible America was to a Nazi attack.

So he ordered his military to devise a plan.

He recruited a team of Germans to board two U-boats headed for the U.S.

On June 13, 1942, one group reached shore in New York and was almost immediately discovered by a Coast Guard member.

The men escaped, but by morning, the Coast Guard had unearthed the Germans' buried supplies, fuses, pre-made bombs, and four crates of TNT.

The German cruise leader decided to turn the others in. He had never been that keen on

carrying out Hitler's orders anyway. So he boarded a train for Washington to meet with FBI agents.

He expected the FBI to welcome him as a hero. They didn't. Instead, J. Edgar Hoover, the infamous FBI director, announced that a German

invading force had been found and that the FBI had captured all of its members. There was

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