The Great Lakes cover nearly 95,000 square miles (250,000 square kilometers) and hold over 20% of Earth’s surface fresh water. More than 30 million people in the U.S. and Canada rely on them for drinking water. The lakes support a multibillion-dollar maritime economy, and the lands around them provided many of the raw materials – timber, coal, iron – that fueled the Midwest’s emergence as an industrial heartland.
Despite their enormous importance, the lakes were degraded for well over a century as industry and development expanded around them. By the 1960s, rivers like the Cuyahoga, Buffalo and Chicago were so polluted that they were catching fire. In 1965, Maclean’s magazine called Lake Erie, the smallest and shallowest Great Lake, “an odorous, slime-covered graveyard” that “may have already passed the point of no return.” Lake Ontario wasn’t far behind.
