Lake Superior is the largest freshwater lake by surface area in the world.

The longer version

Surface area measures the extent of the water, while volume depends on depth as well. A lake can lead in one measure and not the other. This one spreads over a huge area carved by glacial ice, with a basin of ancient rock that resisted erosion. Its shoreline is long and deeply indented.

Its large size gives it a slow response to weather, since the water holds heat into autumn and cools gradually. Storms on open water can be severe because wind travels unobstructed for long distances. Cold, clear water supports fish species that need low temperatures to thrive. Ice cover forms in winter but rarely seals the whole surface.

Where this entry sits

These facts wander across maps, borders, deserts, rivers, mountains, and the extreme corners of the natural world. Each one is short and self-contained, offering a small surprise about places you may never visit rather than anything you actually need. The full list sits on the Geography page, where every entry is listed in order.