Michigan isn’t called “the Great Lake state” for nothing. No matter where you go in the state, you’ll never venture more than 85 miles away from at least one of the Great Lakes. And hidden within those lakes are thousands of historic shipwrecks — 1,500 of which are owned by Michigan itself.

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The statistic comes from Laura Ashlee, who works for the Michigan State Historic Preservation Office. Last week, she dropped the staggering number of state-owned shipwrecks in an interview given to MLive’s Stephen Kloosterman, who was reporting on recent revelations that a ship thought to be a French wreck that disappeared in the seventeenth century wasn’t in fact the earliest-known shipwreck on the Great Lakes.

Why does Michigan possess so many wrecked ships? Chalk it up to the Great Lakes’ historic importance as a commercial shipping route. The Michigan Shipwreck Research Association estimates that a total of 6,000 ships litter the bottom of the Great Lakes, deposited there by the ravages of weather, human error and just plain bad luck.

Because the Great Lakes are chilly and fresh, they do a great job of preserving wrecked vessels. Clear waters can make the vessels visible from the air, but the real treasures lie beneath the surface.

“Clearly the remains of these vessels are invaluable,” writes former Michigan State Archaeologist John Halsey. But, he notes, that doesn’t mean every state has always taken shipwrecks seriously. It’s hard to find and document shipwreck sites, let alone find funds to preserve them. Another problem, writes Halsey, is sport divers — though they are often the primary parties to explore and locate shipwrecks, their activities sometimes disturb invaluable artifacts.

That led to the creation of Michigan’s underwater preserve system in the 1980s. UpNorthLive’s Brody O’Connell reports that the system keeps shipwrecks open to divers as long as they don’t disturb or remove underwater artifacts. Tamper with a wreck, and you could face felony charges, equipment confiscation, and even prison time.

Still, sport divers are an invaluable source of information about shipwrecks. Organizations like the Michigan Shipwreck Research Association work with divers to help assess, explore, document and interpret what lies beneath, while the state gathers information about wrecks from divers who make sometimes astonishing finds.

But watch out — shipwreck diving can become an addiction. In the words of the Michigan Underwater Preserve Council, “after diving in any of Michigan’s underwater preserves, you may find yourself wanting to try them all.”