Greenland looks as big as Africa. On the Earth, Africa is almost 14 times larger.

On a Web Mercator map, Greenland is drawn at 35.40 million square kilometers and Africa at 33.52 million. On the WGS 84 ellipsoid, Greenland covers 2.17 million and Africa 29.89 million. Both outlines are correct: the map projection is what changes their size.