I am bizarrely captivated by this illustration of "Everyone Who’s Immigrated to the U.S. Since 1820":
http://metrocosm.com/animated-immigration-map/
A more depressing version is this animated map of slave ships crossing the Atlantic between the 16th and 19th centuries:
http://www.slate.com/articles/life/..._the_history_of_the_atlantic_slave_trade.html
If you pause the animation and click on a dot, you can find out more details about the ship. It's part of a huge project to catalog the trans-Atlantic slave trade:
http://slavevoyages.org/