Lake Superior Isn't Really a Lake. It's a Wound.

Lake Superior is not shaped like a lake. It is long, narrow and curving — and if you trace that curve past the shoreline it keeps going, southwest through Minnesota, Iowa and Kansas, and southeast into Michigan. That is not a glacial basin. That is a rift. Around 1.1 billion years ago North America tried to tear itself in half. The Midcontinent Rift opened, roughly two million cubic kilometres of basalt poured out, and then it stopped. The continent stayed in one piece — but the scar sagged under the weight of its own lava and kept sinking for a billion years. Ice found the weak trough, gouged it out, melted, and filled it. 15 facts about what is under that water: 1800s shipwrecks still sitting upright with the lettering legible, copper mined with stone hammers 7,000 years ago and traded a thousand miles, iron ore that recorded the day Earth's atmosphere changed, a single lock chamber holding up American steel, and a lake floor 700 feet below sea level in the middle of a continent. CHAPTERS 0:00 The lake that hides a billion-year-old secret 0:51 #15 Ten percent of the world's fresh surface water 2:17 #14 Water that stays in the basin for 190 years 3:23 #13 The lake that kills storms and makes its own snow 4:34 #12 Seiches - the lake that tilts 5:44 #11 Why 1800s shipwrecks are still intact down there 6:59 #10 Native copper and the Old Copper Complex 8:34 #9 The Stone Age supply chain that crossed a continent 9:31 #8 Banded iron and the day the atmosphere changed 10:48 #7 Taconite - the waste rock that saved an industry 11:52 #6 The Poe Lock - one chamber holding up US steel 12:51 #5 The 1,000-foot ships that can never leave 13:55 #4 The basin is still tilting southward 15:04 #3 A lake floor 700 feet below sea level 16:06 #2 Two million cubic kilometres of lava 17:19 #1 The Midcontinent Rift - the wound under the lake WHAT'S COVERED - Around 3 quadrillion gallons — more water than the other four Great Lakes combined, with room for three more Lake Eries - A retent