Timelines are extremely useful visual devices for understanding how events in history relate to each other, and for getting a sense of the "flow" of history. Reading a list of dates and events in a table is never as interesting as poring over a detailed timeline.
Unfortunately, there's not a lot of precedence for using timelines on the web. They tend to be static images or they just feel hacked together.
TimelineJS seeks to help web devs create responsive, interactive timelines--bringing the timeline into Web 2.0 and the 21st century.
With the open-source TimelineJS, you can easily put together a timeline that functions a bit like a slider, but includes interactive features. You can easily add Youtube videos, Wikipedia excerpts, blockquotes, links to other sites, Google maps, Vine videos, Flickr pictures, and even tweets (because, after all, history does happen on Twitter these days).
Pretty cool. Here's a video tutorial to show you how easy it is: