Quentin Hardy reports in The New York Times that Kalev Leetaru, a researcher at the University of Illinois, has mined Wikipedia to reveal the connections between cities around the globe over time, focusing on the type of language used to talk about a particular place, to see whether the writers have a generally positive or negative sentiment toward the place at that time.

The result is “an interesting historical atlas of the rise of globalization and warfare….Leetaru said his work was meant to be a snapshot of how Wikipedia writers of today view the world, and not a decisive verdict of history. Examining the content of books and other print media written over a longer period might well register different, and changing, sentiments about historical events over time.” In the time-lapse movie below, each location is plotted against the date referenced and cross referenced when mentioned with other locations. The sentiment of the reference is expressed from red to green to reflect negative to positive.