If you go

The Patriots Point Naval & Maritime Museum is commemorating the 70th anniversary of D-Day by hosting a symposium that will feature two guest speakers, one who was aboard the destroyer Laffey the day of the attack and an Army Ranger who landed on Omaha Beach.

The admission-free symposium will start at 7 tonight, inside the aircraft carrier Yorktown's Smokey Stover Theater. Parking for the event will cost $5.

The Laffey, docked at Patriots Point, is one of only two D-Day warships still in existence. There were more than 5,000 floating off the shore of German-occupied France the day of the attack.

The symposium will feature entertainment and a living history production on the D-Day invasion and the breakout from Omaha Beach.

The tanks never had a chance.

There are three of them, M-7 Priests, lying close together on the floor of the English Channel, just off the coast of Normandy.

They came to rest there 70 years ago, while trying to make their way onto Omaha Beach during the largest amphibious assault in history, the D-Day landing.

They were waterproof, equipped with propellers, and dove into the water from landing craft - and sank to the bottom.

"They worked great in calm water," said Ralph Wilbanks, a Charleston underwater archaeologist. "But with 6,000 ships in that water, the seas had to be 6 to 8 feet. I don't think they could handle it."

Wilbanks traveled to France last summer to volunteer for the largest survey ever of the D-Day site. In a month, he and an international team searched 200 square nautical miles off the French coast to see what remained of the most daring, complex and successful military operation of World War II.

The results of the operation can be seen in PBS's NOVA special, "D-Day's Sunken Secrets."

Wilbanks has found hundreds of wrecks in his career - he led Clive Cussler's dive team that found the Confederate submarine H.L. Hunley off of Sullivan's Island - but never had he found hundreds of wrecks in the course of a few weeks.

In a month, the team found 450 targets, more than 200 of them military vehicles - mostly landing craft. The waters off those beaches are a hidden battlefield, a cemetery, and the closest anyone can come these days to understanding the sheer scope of the Allied Forces efforts to retake Europe from the Germans.

Wilbanks helped locate landing craft, tanks and the troop transport ship Susan B. Anthony.

Below the surface of the turbid water, there are remnants of the floating bridges, caissons and breakwaters used to build artificial harbors, which were called Mulberries.

Wilbanks said looking at the massive structures and realizing that 1940s technology designed and built these things on short order showed him why those men helped define the Greatest Generation.

A love of history led Wilbanks to volunteer his time to the project. About 15 years ago, he joined a Navy expedition to map the site but was unhappy with the results.

"I always felt those guys deserved a better survey," he said.

The work was tedious. Wilbanks and an international team worked from a catamaran, using side-scan sonar and other electronic search techniques to map the floor. He worked 12-hour days for a month, and went ashore only three times.

The survey averaged a new target nearly every hour. And there is no telling what is still there buried beneath the sand.

Nearly 6,000 vessels were part of the total invasion force, more than 4,000 landing craft carrying troops, supplies or guns. More than 150,000 troops were part of the first wave. Many of these men and landing craft did not make it. One day, Wilbanks found a landing craft that had clearly been blown apart by a mine.

As a result of this team's work, France is seeking to have the waters off Normandy declared a World Heritage site.

Wilbanks said he is more convinced than ever that the waters off the French coast are worthy.

"You see all this stuff, realize how complicated it was, and you wonder what would have happened if it had failed," he said.

But it didn't fail. The other thing this survey showed was that many more of the 7,000 vessels on the water during D-Day made it on to the beaches of Normandy than ended up at the bottom of the English Channel.

Including the tanks.