The age of sail, visualized
As anyone who's ever played Civilization[*] knows, the advent of sailboats capable of crossing the oceans leads to an explosion of exploration, commerce and social development. And with the visualization below, you can see that explosion in action:
Ben Schmidt used the R language and data recorded in by hand in ship logs[**] to create the animation above. Like all good data visualizations, it's not just fascinating to look at, it draws the viewer in to inspect the details and wonder. For example, at around 3:25 check out the flotilla of Spanish ships leaving the east and west coasts of South America in the early 1778 and converging on Europe in the summer. I'm no history buff[*] and a little Googling didn't reveal what this was all about -- does anyone know? Ben points out other historical events, such as Captain Cook's exploration of the south Pacific in 1772-1775.
In sailing, the weather certainly was a factor, which leads to another cool detail: that bouncing month indicator isn't just there for show. The month is positioned at location of the sun at noon in Africa - when it's near the the south it indicates summer in the southern hemisphere, and summer in the North when it's near Egypt. Ben has also created a seasonal version of the chart, showing all of the voyages of the period by month. You can see that animation, plus much more detail and commentary from Ben about the shipping data themselves, at the link below.
[*] Or has read a history book, I suppose.
[**] The story of how these data were discovered is also fascinating.
Sapping Attention: Visualizing Ocean Shipping