The world is sperical, and if you’ve ever seen a map, you may think you know how ffar away bits and pieces of it are from you. And that would be vaguely true, in a geographical sense (well, the maps we see are generally not very geographically correct, but that’s a different story), but in terms of how long it takes you to get from A to B or in terms of how much it will cost you to get from A to B it’s a whole different story.
So this map shows you the distances based on cost and travel time from your point of reference (ie. where you are on the map). Interestingly, Africa is very isolated from almost everywhere, whereas the US and Europe are very very close indeed.