The flow diagram above shows the migration paths from players participating in the FIFA world cup 2014, who were born in another country than the one they are playing for. The more players migrated from one country to another the thicker the line that connects them. You can click on the countries and paths for detailed information of the players who migrated.
The use of the word migration in this context doesn't imply that the concerned players live in the countries they play for. In many cases they were actually raised in the countries they were born in and play for a club there. Often the migration is their best chance to take part in tournaments like the world cup, so it is a perfectly comprehensible move, even more so since they usually have ancestry from the country they play for.
Here are a few tidbits I learned through this visualization and the feedback I got: