The events of D-Day on June 6, 1944, were the result of years of careful planning, deception, good luck, and setbacks. As we near another D-Day anniversary, it is important to understand what transpired before the massive invasion of Normandy. Here are a few highlights that you may have never heard about:

The Tragedy and Massacre at Slapton Sands

In April 1944, in Slapton Sands, Devon, Allied troops conducted a large-scale mock invasion to prepare for the inevitable invasion of Normandy. The training operation was dubbed Exercise Tiger and involved over 30,000 men.

On April 27, a large Allied beach landing was planned. General Eisenhower had ordered British battleships to shell the beach with live rounds, right up until the landing craft landed, in an attempt to prepare soldiers for what they would encounter in Normandy. At the last minute, the invasion was pushed back an hour. But of course, not all of the invasion units learned of this schedule change, resulting in some Higgins boats landing on the beach early and being hit by friendly fire.

The next piece of this story is made up of rumors and cover-ups and has never been confirmed or verified by the United States Government. According to eye-witness accounts and documented stories, the roleplaying defenders on the beach, who were also Allied soldiers, used live ammunition during the training exercise.

Some say that Eisenhower had ordered the defenders to have live ammunition and to shoot over the soldiers’ heads. Others claim that the roleplayers were supposed to be given dummy rounds, but accidentally were supplied with live rounds. The story goes that the soldiers were mowed down on the beach, resulting in the death of somewhere between 300 to 450 soldiers. Yet, as aforementioned, this story is strictly hear-say and has never been officially confirmed.

D-Day: June 6th, 1944

Read Next: D-Day: June 6th, 1944

Unfortunately, things were to only get worse for the Allied mock invasion force.

The night after this fateful invasion, German E-Boats were cruising off the Devon coast and came across a group of Tank Landing Ships (LSTs). These LSTs were a part of an Allied convoy headed to Slapton Sands from Plymouth. They were loaded with soldiers from the U.S. Army’s VII Corps, who were to serve as the second wave of the practice invasion, the next morning. HMS Azalea, a Royal Navy Corvette, was the only escort of the flotilla. The Azalea had identified and reported the E-Boats, but due to communication failures, the rest of the convoy were never made aware of the impending threat.

Needless to say, the LSTs were sitting ducks. The E-Boats successfully torpedoed three landing craft, sinking two of them. Each was loaded with fuel, ammunition, and hundreds of men. The result was grisly. Many soldiers and sailors died instantly and many others drowned or succumbed to hypothermia. Because of the shock and confusion, commanding officers ordered the remaining ships to scatter, contributing to the ghastly death toll. One survivor poignantly said, “You could walk to the beach on the floating bodies.”

General Eisenhower and top Allied staff made it a point to keep the tragedy at Devon a secret. They feared that if it were publicized, the Germans would realize an invasion at Normandy was coming. Soldiers and sailors were threatened with court-martial if they spoke about the disaster. Yet, suspicions were raised when people noticed that hundreds of coffins were being shipped to Devon.

The official death count was 749, surpassing the number of soldiers killed at Utah Beach on D-Day. Chances are the death toll may have been even higher, as this number only includes the dead from the E-Boat attack, but we may never know.

This article is the first article of a series. Stay tuned for the second part.