In 2002, divers in Lake Huron were swimming among the shipwrecks in the Thunder Bay National Marine Sanctuary. The sanctuary protects the remains of almost 100 ships that met their demise when trying to navigate through “shipwreck alley.”
The divers saw the usual sunken schooner. The overturned steamer. The remains of the tugboat. But there was something else. There appeared to be a massive sinkhole near Middle Island, about a mile off the coast of Michigan.
Scientists sent down a remotely operated vehicle (ROV) to get closer to the crater. They soon realized they were looking at an ancient sinkhole, and in the coming years, they would learn there were many others in the Great Lakes.
As technology has enabled researchers to get deeper into the sinkholes, scientists have discovered they are time capsules that offer a glimpse into what life was like billions of years ago.
