Before American soldiers landed on the beaches of Normandy on June 6, 1944, troops were preparing for D-Day on the beaches of South Florida.

They were doing jumping jacks on the sand in Miami Beach.

In the sky were big, green military planes.

That’s because before Florida was prime real estate for waterfront mansions and tourism, it was the perfect place to train soldiers.

Credit Julia Duba A photo of William Hopwood when he served as a Naval communications officer in South Florida during World War II.

“You didn’t have to quit in the middle of the winter because of snow, ice, anything,” says William Hopwood, who was a Naval communications officer in South Florida during World War II.

Because there’s water everywhere, South Florida was a good place to build ships and train soldiers to operate submarines.

“You’re never far from water,” says Anthony Atwood, a retired Naval officer who studies local military history. “The furthest that you are from water in the peninsula is 150 miles maximum.”

Submarine training happened in downtown Miami where Bayside Marketplace is today.

It was important to have that kind of training because German submarines made it pretty close to U.S. shores and sunk ships off the coast of Florida.

“It was only one ship that was sunk right off Miami Beach that could be seen from the shore,” says Hopwood. “It was on fire, it was hit by a torpedo.”

Every night, the city would have to shut off all its lights so it could stay hidden.

Downtown Miami was under naval control. Every now and then, cadets would hold up traffic as they marched up and down Biscayne Boulevard.

The Venetian Pool in Coral Gables was where soldiers learned how to swim. There was a blimp base where Zoo Miami is now. Gas and food were rationed.

There were 25 prisoner of war camps throughout Florida, where German POWs lived and worked. Many of them ended up staying in Florida after the war ended.

Credit Julia Duba William Hopwood in his Coconut Grove home. Hopwood was a Naval communications officer in South Florida during World War II.

“Given that it was a harsher world in many respects, many were happy to be in Florida of all places,” says Atwood.

Soldiers came back and built houses, enrolled in the University of Miami and welcomed more winter tourists than ever before.

“We loved the climate. We wanted to come back,” says Hopwood. “After the war, Florida began to fill up with people who had been stationed here.”