Google officially launched a new feature in Google Earth: featured content, a list of overlays from content providers that add more information about the places you explore in Google Earth. The list of content providers include: Discovery Networks that shows videos from all over the world, National Park Service, United Nations Environmental Program that showcases 100 areas of extreme environmental degradation, Turn Here that offers city guides. Google already showed overlays from National Geographic, most of them in Africa.
You can find Featured Content in Google Earth sidebar, in the Layer section. Click on the checkbox next your favorite sources of content and then double-click on one of them or search for a location and look for the special icons.