| True area | On the old Mercator map | Distortion vs truth |
|---|
| Mauritania | 1,038,352 km² | 1,183,721 km² | 1.1× |
| Greenland | 2,154,754 km² | 25,447,645 km² | 11.8× |
| Africa | 30,370,000 km² | — | 1× |
Old maps drew Mauritania at about 1,183,721 km² km². The truth is 1,038,352 km² km² — a difference of 14%% that school atlases carried for centuries.