A few years ago, while I was working at TWO-N in New York, we entered a data visualization contest. The prompt for the contest was to examine economic values for slaves and soldiers in historical contexts spanning from antiquity to the colonial era (already converted to 2014 US dollars), and compare them to modern day examples of human trafficking and enslavement. Conceptually, it was a very strange and provocative task. Nonetheless, it was an enjoyable project that let me explore some scrolling effects and the element of a large horizontal scroll space to represent the flow of time over thousands of years.
The finished version is at https://s3-us-west-1.amazonaws.com/sheppard-portfolio/human-cost/index.html, with the code at https://github.com/ragingsquirrel3/stellar_scroll_example. In the end, we didn’t win the contest, but got an honorable mention from the judges.
Travis Sheppard 
Very nice Travis. Visual story telling is probably the way to go from now on. I was wondering why you guys did the horizontal scrolling rather than vertical. Are there any studies comparing the effects of those two (horizontal vs vertical scrolling) for effectively conveying the story.
Something like this –
http://www.r2d3.us/visual-intro-to-machine-learning-part-1/
Hey Nikhil, I just got back from a d3 meetup where the creator of the machine learning article (Tony Chu) gave a talk about his work, and I learned that this type of work is called “scrollytelling.” I’m not aware of any studies, but would agree that all else held equal, vertical scrolling is more intuitive. For the human cost piece, we initially tried it vertical, but thought that horizontal worked better for a few reasons. The main reason is that scrolling is used to represent time in our case, and most people abstract time horizontally. The second reason is that while there are plenty of great vertical bar charts, horizontal bar charts are a little more natural. Another reason was that the scrolling effect with the images just worked a lot better in the horizontal version than the initial vertical prototype. All these reasons were enough to justify a departure from vertical scrolling.
good vertical bar chart https://fleximize.com/unicorns/