The British Codebreaker Who Convinced the U.S. to Join WWI

National Archives
National Archives

On January 16, 1917, Nigel de Grey, a cryptologist working for the British military, intercepted a coded German telegram sent via standard diplomatic channels. This alone was nothing special. The British cryptanalytic office where de Grey worked, called Room 40, had cracked a handful of Germany's ciphers and intercepted their messages daily. Today, however, was different: The jumble of numbers revealed a political bombshell.

We intend to begin on the 1st of February unrestricted submarine warfare. We shall endeavor in spite of this to keep the United States of America neutral. In the event of this not succeeding, we make Mexico a proposal of alliance on the following basis: make war together, make peace together, generous financial support and an understanding on our part that Mexico is to reconquer the lost territory in Texas, New Mexico and Arizona.

The coded message, sent by the German Foreign Minister Arthur Zimmermann, was destined for the German Minister in Mexico City. (Along the way, it had passed through Germany's ambassador in Washington, D.C., Count Johann Heinrich von Bernstorff.) At the time, America was not involved in the Great War. In fact, President Woodrow Wilson had just secured a second term by riding the slogans "He Kept Us Out of War" and "American First." The decrypted message plainly indicated that Germany was hoping Wilson would stick to his campaign trail talking points.

But the message also showed that Germany was afraid. An escalation of submarine warfare could provoke the United States, compelling it to abandon its isolationist policies and enter the war. If that happened, Germany hoped to distract the U.S. by forcing American troops to focus on an enemy closer to home: Mexico.

Upon realizing the message's significance, de Grey immediately sprinted to the office of his superior, William Reginald "Blinker" Hall.

"Do you want America in the war, Sir?" he shouted.

Hall gave de Grey, who was gleaming with sweat, an incredulous look. "Yes, why?"

"I've got a telegram that will bring them in if you give it to them."

According to an exhibit at the National Cryptologic Museum in Fort Meade, Maryland, "[The British] realized that they held a cryptanalytic 'trump card' that virtually guaranteed America's entry into WWI on the Allied side." Historian David Kahn put it thusly: The "codebreakers held history in the palm of their hands."

When a select few in the U.S. federal government were finally notified of the secret message, many doubted its authenticity, believing it was just a deceitful ploy by the British to win American support. The British assuaged those doubts by acquiring a fresh copy of the coded telegram and handing it over to the Americans. On February 23, a U.S. diplomat saw the message be decrypted with his own eyes—again with the help of codebreaker Nigel de Grey—and independently verified Germany's intentions. The diplomat immediately contacted President Wilson.

When Wilson saw it, he was shocked and insulted. "Good Lord! Good Lord!" he shouted. About one week later, he leaked the message to the press. Americans were similarly outraged.

(As for Mexico, the country knew it was getting a raw deal and never took Germany's bait. Reclaiming the American southwest—what was formerly Mexican territory before the Mexican-American War in the 1840s—was a recipe for disaster. Besides, Germany would have never been able to help anyway: They were blocked by the British Navy.)

By early April, the secret code had compelled the U.S. to join Britain and its allies. Today, the work of de Grey and the other Room 40 codebreakers is widely considered one of the most consequential events in cryptologic history.

 

Hungry for more details about the Zimmermann telegram? Mental Floss’s coverage of the World War I Centennial has you covered here and here.

15 Convenient Products That Are Perfect for Summer

First Colonial/Lunatec/Safe Touch
First Colonial/Lunatec/Safe Touch

The Fourth of July is the epitome of summer—and after several months spent indoors, you need some outdoor fun more than anything. Check out these 15 summer must-haves while they’re on sale and save an extra 15 percent when you spend $50 or more with the code JULYFOURTH15.

1. CARSULE Pop-Up Cabin for Your Car; $300 (20 percent off)

Carsule tent from Mogics.
Mogics

This tent connects to your hatchback car like a tailgate mobile living room. The installation takes just a few minutes and the entire thing stands 6.5 feet tall so you can enjoy the outdoors from the comfort of your car.

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2. Mosquito Killer Lamp; $30 (25 percent off)

Mosquito-killing lamp.
Kinkoo

If you just so happen to be one of those unlucky souls who attracts a suspicious amount of mosquitos the second you step outside, you need this repellent lamp to help keep your arms and legs bite-free. It uses a non-toxic combination of LED lights, air turbulence, and other methods to keep the pests at bay.

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3. Super Shield Mosquito Repellent Electronic Watch Band; $17 (57 percent off)

Mosquito repeller watch.
Safe Touch

While a lamp is a great non-toxic solution for keeping bugs at bay, active individuals need a bug repellent that can keep up with their lifestyle. This wrist wearable keeps you safe from mosquitoes anywhere by using ultrasonic sounds to drive them away.

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4. ZeroDark 3-Piece Tactical Set: Flashlight, Lantern, and Headlamp; $20 (66 percent off)

Aduro flashlight set.
Audro

If you want your summer to be lit, this set will do the trick. All puns aside, this trio of LED brightness is perfect for camping fun and backyard parties, or it can be stored in the car for emergencies.

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5. Outdoor Collapsible Cooler and Camp Table Set; $64 (27 percent off)

First Colonial cooler.
First Colonial

Cookouts are easy with this cooler and table set that chills your drink until you're ready to pop it into one of the four convenient cupholders. Bring this set camping or out by the pool for convenience anywhere.

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6. Trident: Underwater Scooter; $550 (21 percent off)

Trident underwater scooter.
Geneinno

If you’ve ever dreamed of better mobility while exploring the water, you’re not alone. The Trident underwater scooter, which raised over $82,000 on Indiegogo, can propel you through the water at up to nearly 6 feet per second, which isn't that far off from how fast Michael Phelps swam in his prime. The battery on it will last 45 minutes, allowing you to traverse with ease.

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7. Go Portable Solar Oven; $119 (14 percent off)

GoSun solar grill.
GoSun

Bake, roast, steam, or broil anywhere you bring this portable oven. Measuring in at just over a foot long and weighing only two pounds, the oven will work in most daytime weather conditions and can hold around 13 ounces of food.

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8. 3-in-1 Waterproof Bug Zapper Lantern; $25 (50 percent off)

3P Experts bug zapper.
3P Experts

Mosquitoes tend to be a big problem at night, partly because it's hard to swat in the dark. This lantern will light the area and zap mosquitos from nipping at you in the process.

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9. Urban E-Skateboard: Basic Version (Orange); $120 (73 percent off)

Urban Rover E-Skateboard
Urban Rover

This e-skateboard is perfect for getting around during the summer. You'll catch a breeze while you’re cruising on the battery-powered platform and won’t break a sweat when you pop the compact board in your bag.

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10. H2 Headlamp: Waterproof, Rechargeable LED Wide 180° Angle Headlight; $37 (26 percent off)

Headlamp from One80Light
One80Light

Camping, car troubles, and sports all pose a problem at night. This LED headlight will light up your surroundings across a 180-degree radius for prime visibility, meaning your outdoor activities won't have to stop when the sun sets.

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11. Whirlwind Cool Bladeless Mini Fan; $22 (63 percent off)

Bladeless fan
Whirlwind

This portable fan comes in a powerful handheld size so you can keep cool while on the move. Unlike other portable fans, this one has a sleek, bladeless design and features three different speeds.

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12. Bladeless Personal Fan; $22 (63 percent off)

Bladeless fan
3P Tech

This bladeless fan won't just keep you cool while you work on your laptop—it also has a built-in rechargable battery that you can use to charge your phone.

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13. MOGICS Coconut: Portable Waterproof Light; $37 (24 percent off)

Mogics portable lamp.
Mogics

This portable light is designed to adapt to your lighting preference. It self-inflates in a few seconds and can bounce, get wet, and set the mood.

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14. Lunatec 1L Hydration Spray Water Bottle; $25 (21 percent off)

Lunatec spray water bottle.
Lunatec

A water bottle can do more than hydrate you. This one has a spray nozzle that can create shower, stream, and mist patterns for doing dishes while camping, sharing a sip without sharing germs, and washing off those muddy shoes after a long hike.

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15. Sport Force Hydration Backpack; $25 (68 percent off)

Hydration backpack.
It's All Goods

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13 Memorable Facts About D-Day

American troops landing on Omaha beach at Normandy on D-Day.
American troops landing on Omaha beach at Normandy on D-Day.
Keystone/Getty Images

The Normandy landings—an event better known as “D-Day”—became a pivotal moment in the Second World War. Heavy losses were inflicted on both sides, but with planning, deception, and semiaquatic tanks, the Allied forces pulled off what is considered the biggest amphibious invasion in history. Here are a few things you should know about the historic crusade to liberate France from Nazi Germany.

1. D-Day occurred on June 6, 1944.

The D-Day invasion was several years in the making. In December 1941, the United States formally entered World War II. Shortly thereafter, British and American strategists began entertaining the possibility of a huge offensive across the English Channel and into Nazi-occupied France. But first, the Allies swept through northern Africa and southern Italy, weakening the Axis hold on the Mediterranean Sea. Their strategy resulted in Italy’s unconditional surrender in September 1943 (though that wasn’t the end of the war in Italy). Earlier that year, the Western allies started making preparations for a campaign that would finally open up a new front in northwestern France. It was going to be an amphibious assault, with tens of thousands of men leaving England and then landing on France’s Atlantic coastline.

2. Normandy was chosen as the D-Day landing site because the Allies were hoping to surprise German forces.

Since the Germans would presumably expect an attack on the Pas de Calais—the closest point to the UK—the Allies decided to hit the beaches of Normandy instead. Normandy was also within flying distance of war planes stationed in England, and it had a conveniently located port.

3. D-Day action centered around five beaches that were code-named "Utah," "Omaha," "Gold," "Juno," and "Sword."

American assault troops and equipment landing on Omaha beach on the Northern coast of France.
Fox Photos/Getty Images

Altogether, the D-Day landing beaches encompassed 50 miles of coastline real estate [PDF]. The Canadian 3rd Division landed on Juno; British forces touched down on Gold and Sword; and the Americans were sent to Utah and Omaha. Of the five beaches, Omaha had the most bloodshed: Roughly 2400 American casualties—plus 1200 German casualties—occurred there. How the beaches got their code-names is a mystery, although it’s been claimed that American general Omar Bradley named “Omaha” and “Utah” after two of his staff carpenters. (One of the men came from Omaha, Nebraska, while the other called Provo, Utah, home.)

4. Pulling off the D-Day landings involved some elaborate trickery to fool the Nazis.

If the Allies landed in France, Hitler was confident that his men could repel them. “They will get the thrashing of their lives,” the Führer boasted. But in order to do that, the German military would need to know exactly where the Allied troops planned to begin their invasion. So in 1943, the Allies kicked off an ingenious misinformation campaign. Using everything from phony radio transmissions to inflatable tanks, they successfully convinced the Germans that the British and American forces planned to make landfall at the Pas de Calais. Duped by the charade, the Germans kept a large percentage of their troops stationed there (and in Norway, which was the rumored target of another bogus attack). That left Normandy relatively under-defended when D-Day came along.

5. D-Day was planned with the help of meteorologists.

The landings at Normandy and subsequent invasion of France were code-named “Operation Overlord,” and General Dwight D. Eisenhower (the future U.S. president) led the operation. To choose the right date for his invasion, Eisenhower consulted with three different teams of meteorologists, who predicted that in early June, the weather would be best on June 5, 6, or 7; if not then, they'd have to wait for late June.

Originally, Eisenhower wanted to start the operation on June 5. But the weather didn’t cooperate. To quote geophysicist Walter Munk, “On [that date], there were very high winds, and Eisenhower made the decision to wait 24 hours. However, 24 hours later, the Americans predicted there would be a break in the storm and that conditions would be difficult, but not impossible.” Ultimately, Ike began the attack on June 6, even though the weather was less than ideal. It’s worth noting that if he’d waited for a clearer day, the Germans might have been better prepared for his advance. (As for the dates they'd suggested for late June? There was a massive storm.)

6. "D-Day" was a common military term, according to Eisenhower's personal aide.

A few years after Eisenhower retired from public life, he was asked if the “D” in “D-day” stood for anything. In response to this inquiry, his aide Robert Schultz (a brigadier general) said that “any amphibious operation has a ‘departed date’; therefore the shortened term ‘D-Day’ is used” [PDF].

7. D-Day was among the largest amphibious assaults in military history.

U.S. troops in landing craft, during the D-Day landings.
Keystone/Getty Images

On D-Day, approximately 156,115 Allied troops—representing the United States, the United Kingdom, Canada, Australia, Belgium, Czechoslovakia, France, Greece, New Zealand, Norway, and Poland—landed on the beaches of Normandy. They were accompanied by almost 7000 nautical vessels. In terms of aerial support, the Allies showed up with more than 10,000 individual aircrafts, which outnumbered the German planes 30 to one.

8. On D-Day, floating tanks were deployed by the Allies.

The brainchild of British engineers, the Sherman Duplex Drive Tanks (a.k.a. “Donald Duck” tanks) came with foldable canvas screens that could be unfurled at will, turning the vehicle into a crude boat. Once afloat, the tanks were driven forward with a set of propellers. They had a top nautical speed of just under 5 mph. The Duplex Drives that were sent to Juno, Sword, and Gold fared a lot better than those assigned to Omaha or Utah. The one at Omaha mostly sank because they had to travel across larger stretches of water—and they encountered choppier waves.

9. When the D-Day attack started, Adolf Hitler was asleep.

On the eve of D-Day, Hitler was entertaining Joseph Goebbels and some other guests at his home in the Alps. The dictator didn’t go to bed until 3 a.m. Just three and a half hours later, at 6:30 a.m., the opening land invasions at Normandy began. (And by that point, Allied gliders and paratroopers had been touching down nearby since 12:16 in the morning.) Hitler was finally roused at noon, when his arms minister informed him about the massive assault underway in Normandy. Hitler didn’t take it seriously and was slow to authorize a top general’s request for reinforcements. That mistake proved critical.

10. DWIGHT Eisenhower was fully prepared to accept blame if things went badly on D-Day.

General Dwight D Eisenhower watches the Allied landing operations from the deck of a warship in the English Channel on D-Day.
Keystone/Getty Images

While Hitler was partying in the Alps, Eisenhower was drafting a bleak message. The success of Operation Overlord was by no means guaranteed, and if something went horribly awry, Ike might have had no choice but to order a full retreat. So he preemptively wrote a brief statement that he intended to release if the invasion fell apart. “Our landings in the Cherbourg-Havre area have failed to gain a satisfactory foothold and I have withdrawn the troops,” it said. “My decision to attack at this time and place was based upon the best information available. The troops, the air and the Navy did all that bravery and devotion to duty could do. If any blame or fault attaches to the attempt it is mine alone.”

11. Knocking out German communications was one of the keys to victory on D-Day.

Hitler may not have had all of his troops in the right spot, but the Germans who’d been stationed at Normandy did enjoy some crucial advantages. At many localities—Omaha Beach included—the Nazi forces had high-powered machine guns and fortified positions. That combination enabled them to mow down huge numbers of Allied troops. But before the dawn broke on June 6, British and American paratroopers had landed behind enemy lines and taken out vital lines of communication while capturing some important bridges. Ultimately, that helped turn the tide against Germany.

12. Theodore Roosevelt's son earned a medal of honor for fighting on D-Day.

It was the 56-year-old brigadier general Theodore Roosevelt Jr. who led the first wave of troops on Utah Beach. The men, who had been pushed off-course by the turbulent waters, missed their original destination by over 2000 yards. Undaunted, Roosevelt announced, “We’re going to start the war from right here.” Though he was arthritic and walked with a cane, Roosevelt insisted on putting himself right in the heart of the action. Under his leadership, the beach was taken in short order. Roosevelt, who died of natural causes one month later, was posthumously awarded the Medal of Honor.

13. D-Day was the opening chapter in a long campaign.

The Normandy invasion was not a one-day affair; it raged on until Allied forces crossed the River Seine in August [PDF]. Altogether, the Allies took about 200,000 casualties over the course of the campaign—including 4413 deaths on D-Day alone. According to the D-Day Center, “No reliable figures exist for the German losses, but it is estimated that around 200,000 were killed or wounded with approximately 200,000 more taken prisoner.” On May 7, 1945—less than a year after D-Day—Germany surrendered, ending the war in its European Theater.