Imagine you can see 160 years of history, all on one screen. You can zoom and pan, you can look at a particular day, you can even do a search. And when you do, the results come up not as a list, but as a heat map that shows where in history that topic appears, and how often. · http://www.lucidimagination.com/blog/2011/06/01/beyondtrees-and-the-new-york-times-using-lucene-to-build-a-time-machine/