Buy the Guardian from Saturday 18 April 2009 to Friday 25 April 2009 to collect the free World Factfile booklets profiling 195 countries. On Saturday we are giving away a free map of the world to mark the start of our series on countries.



The projection we have used is commonly known as the Mercator projection (a projection being any method of representing the surface of a sphere on to a flat plane). The Mercator is well-known and familiar: it is the standard map used in most schoolbooks and newspapers; it arguably has the clearest depiction of all countries included in our world factfiles series.



But it isn't without its problems: since it is mathematically impossible to "flatten" the Earth onto a rectangular sheet of paper without distorting the outline or proportions of the continents, every projection has its own set of advantages and disadvantages.



Click your way through this gallery for a tour of less familiar views on the world