Click here to see how U.S. religious landscape has changed in nearly two decades.
This visual was published by USA Today back in March, 2009. It represents multiple levels of information in one graph. It makes it easy to see broad trends without leaving out the detail.
How did they do it? They color coded each state to correspond with their region. At a glance you can see the response distribution for each region, while still being able to mouse over the visual to find your individual state.
I thought it was an interesting concept since many times data gets lost when trying to visually summarize it.