What does the map show?

For 2014 World Cup players, where are they born and where are they playing

Where do the squads list and player information come from?

The information come from wikipedia: http://en.wikipedia.org/wiki/2014_FIFA_World_Cup_squads

Where does the information on player's value come from?

From transfermakt: http://transfermarkt.co.uk/

What is the difference between the icon colors?

<= 5M€ (a player costs less than 5M€ according to transfermarkt)

<= 10M€

<= 20M€

> 20M€