What is the best way to display a websites visitors by location?

Though, the title is self-explanatory, I would like to ask you for your opinion on what is the best technique to use, to visualize geolocation data of the users, who visited your website. This includes country, state/province, city, etc. Should I use any maps? Or should I use a pie-chart? I'm stuck with this for a week now, so any help would be greatly appreciated. :)

Thanks in advance!