On a Mercator map Greenland looks as big as Africa. It is 14 times smaller.
The map on most walls and screens stretches everything away from the equator. Guess how badly, then drag a country north and south and watch its size change while its real area stays put.
Step 1 / Your guess
Take any shape. Slide it from the equator to 72° north (the latitude of Greenland's centre) on a Mercator map. By what factor does its area grow?
Your guess: 4×
Step 2 / Drag a country
Solid disc: the size it is drawn at. Dashed ring: the size it really has. The red ring is Africa's true area at the equator, for scale.
Step 3 / The ranking flips
The ten countries that look biggest, by true area or by area as drawn at the latitude of their centre.
Step 4 / Every country
Tap a column to sort. Tap a row to load it in step 2.