1
⬇️
Go Deeper
The Great Lakes exist because glaciers the size of mountains carved massive valleys across North America during the last Ice Age, then melted and filled them with water.
2
⬇️
Go Deeper
During the last glacial period, ice sheets over a mile thick scraped the bedrock like a giant file, creating interconnected basins that couldn't drain naturally afterward.
3
⬇️
Go Deeper
The glaciers didn't just carve downward—they pushed sediment ahead of them, creating natural dams that trapped meltwater and shaped the lakes' exact boundaries today.
4
⬇️
Go Deeper
Lake Superior's basin formed when glaciers exploited a weak zone in ancient bedrock, making it Earth's largest freshwater lake by surface area.
5
⬇️
Go Deeper
The lakes' water levels still rise and fall because the land beneath them is slowly rebounding upward after the glacier's immense weight finally lifted.
6
⬇️
Go Deeper
Isostatic rebound means the northern lake shores are rising while southern shores sink, gradually tilting the entire Great Lakes system over millennia.
7
⬇️
Go Deeper
Lake Michigan is sinking while Lake Superior's north shore rises, eventually forcing water to flow differently between the lakes in thousands of years.
8
⬇️
Go Deeper
The Great Lakes' outlet shifted dramatically when glaciers retreated, causing ancient water to suddenly drain northward into Hudson Bay instead of southward.
9
⬇️
Go Deeper
The lakes' drainage reversal happened so fast it created Niagara Falls—a waterfall that's actively eroding backward toward Lake Erie at measurable rates today.
10
⬇️
Go Deeper
COMPLETE
Niagara Falls erodes backward roughly one meter per year, meaning it'll reach Lake Erie in about 50,000 years, fundamentally reshaping North America's hydrology.
Three ways to keep going — in the app:
Where would you have taken it? Fork this trail in the app and steer it your own way.
Make a trail about your world
That was 10 levels, two sentences at a time — no wall of text. Your kid's obsession, a health question, your weirdest hobby: see who actually reads what you share.
