Today in History - April 18: Fake radio station tricks hundreds of thousands of soldiers into surrendering

Hundreds of thousands of German troops surrendered to American forces on April 18, 1945, based on something they had heard on the radio.

The troops of Germany's immense Army Group B believed they had been completely encircled.

But what they didn't know was that there was a 24km gap through the mountains through which the army could have safely retreated to continue the war.

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The Germans would have been aware of this had they trusted their own intelligence.

But they were led to believe they had been surrounded by a German-language radio station they had been listening to for months.

They weren't to know the station had for months been operating behind enemy lines, earning their trust with seemingly pro-Nazi propaganda.

Operation Annie was a fake propaganda radio station that operated for more than 100 days during World War II.

Broadcasting from Luxembourg, the station would play German folk and classical music as well as news updates on the state of the war.

Because of its accuracy and milder tone to other Nazi stations, it had gained a following among Germans, especially soldiers.

After building up its audience, Operation Annie's mission changed. 

The Allied forces had broken through at the start of that month, surrounding 370,000 German soldiers.

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But a slight gap in the line threatened to allow the army to slip through and fight another day.

The radio station broadcast to the Germans reports of a safe escape route.

Elements of Army Group B headed to the spot, only to meet prepared US defenders.

The broadcast had directed the Germans away from the true gap in the line towards a spot from which they stood no chance of retreat.

Shortly afterwards, the army surrendered en masse.

Germany signed an unconditional surrender on May 8 that year.

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