Short answers, pulled from the story.
The five Great Lakes are Superior, Michigan, Huron, Erie, and Ontario. They form a series of large interconnected freshwater lakes spanning the Canada-United States border. Hydrologically, Michigan and Huron are a single body of water joined at the Straits of Mackinac.
The Great Lakes contain more than 20% of the world's surface fresh water by volume. They are the largest group of freshwater lakes on Earth by total area and the second-largest by total volume. They hold about 84% of the surface fresh water of North America.
The Great Lakes formed at the end of the Last Glacial Period, after the Wisconsin glaciation ended 10,000 to 12,000 years ago. As the Laurentide Ice Sheet receded, meltwater filled the basins the glaciers had carved. The foundational geology dates back 1.1 to 1.2 billion years to the Midcontinent Rift.
Lake Michigan is the only Great Lake entirely within the United States. The other four lakes form a water boundary between the United States and Canada. Lake Michigan is also the largest lake by surface area that lies wholly within a single country.
Invasive species in the Great Lakes include the zebra mussel, discovered in 1988, and the quagga mussel, found in 1989, whose numbers in Lake Michigan are estimated at 900 trillion. Others include the round goby, the ruffe, the sea lamprey, and Asian carp. On average a new species enters the lakes every eight months.
The Lake Superior shipwreck coast from Grand Marais, Michigan, to Whitefish Point became known as the Graveyard of the Great Lakes because more vessels have been lost there than anywhere else on Lake Superior. The lakes are prone to sudden severe autumn storms from late October until early December. Hundreds of ships have sunk in the lakes.
The total surface area of the Great Lakes is approximately 94,250 square miles, nearly the same size as the United Kingdom. The Great Lakes coast measures about 10,500 miles, with Canada bordering roughly 5,200 miles and the United States 5,300 miles. Michigan has the longest shoreline, at roughly 3,288 miles.