Historians are pretty good at tracking down concrete events that took place in our past. But unless you lived through all the wars, plagues, celebrations, explorations and revolutions, it's hard to imagine the sentiments and emotions that underscores the world's history.
Kalev Leetaru, who works as a researcher of the University of Illinois Graduate School of Library and Information Science, decided to map out the brief history of the world's emotions based on English-language entries found on Wikipedia.
The articles were loaded into a computer program that identified each location and date mentioned, and linked connections between them. Leetaru then cross-referenced those factors with the positive or negative sentiment represented in the text.
The final result is this sentiment-through-time visualization, which depicts the positive (green) or negative (red) sentiments unfolding through Wikipedia through space and time: