Google is testing a new feature for its Knowledge Graph, which lets users explore timelines for select queries.
Florian Kiersch, who frequently identifies Google features in testing, posted a video showing the functionality on Google+ (via Search Engine Roundtable):
It's unclear what all types of queries might display this type of result, but the video shows queries for Google, Andy Rubin, and "world war".
This could turn out to be a pretty helpful tool, particular for studying, though until Google's Knowledge Graph becomes a more reliable source of information, I wouldn't put too much stock into the accuracy of the information presented, at least without fact checking.
Google was even recently spotted showing brand results in the Knowledge Graph, though this appears to have been a mistake. But that's part of the problem. Google seems to make a lot of mistakes in its "Knowledge" Graph.
Image via Google+