Janie on Twitter pointed me to this South China Morning Post graphic showing off the mighty train line just launched between north China and London (!)
Scrolling down the page simulates the train ride from origin to destination. Pictures of key regions are shown on the left column, as well as some statistics and other related information.
The interactivity has a clear purpose: facilitating cross-reference between two chart forms.
The graphic contains a little oversight ... The label for the key city of Xian, referenced on the map, is missing from the elevation chart on the left here:
I also like the way New York Times handled interactivity to this chart showing the rise in global surface temperature since the 1900s. The accompanying article is here.
When the graph is loaded, the dots get printed from left to right. That's an attention grabber.
Further, when the dots settle, some years sink into the background, leaving the orange dots that show the years without the El Nino effect. The reader can use the toggle under the chart title to view all of the years.
This configuration is unusual. It's more common to show all the data, and allow readers to toggle between subsets of the data. By inverting this convention, it's likely few readers need to hit that toggle. The key message of the story concerns the years without El Nino, and that's where the graphic stands.
This is interactivity that succeeds by not getting in the way.