
The message of the site is utterly to the point, and they take care to present users with the facts that back it up. They balance clean text and carefully selected imagery in a deliberately restrained way that never overwhelms. Like an increasing number of sites today, they have opted for one scrolling page, which makes it easier to casually move through more information without the "commitment" of a click.
But what's most interesting for learning interface designers are their information visualizations, including an elegant interactive timeline, which can be explored in multiple ways, and an interactive travel map with hotspots to drill down to detail. Check it out (and sign the petition).