Drag countries around a true-size map to compare their real area, free of Mercator distortion.
Every flat world map has to distort something, and the Mercator projection distorts area. Countries near the poles are stretched, countries near the equator are squeezed, and generations have learned the shape of the world from a picture that gets size badly wrong.
Greenland looks the size of Africa on a Mercator map. Africa is about fourteen times larger.
Pick any country and drag it across the map. It resizes continuously as it moves, so wherever you drop it you are seeing its real area against the land beneath it. Drag Australia up to Europe, or Greenland down to the equator, and the distortion becomes obvious.
You can compare several countries at once, and group them by region to see how a whole continent measures up.
GK Maps — Where Geography Meets Knowledge.