This page, from the excellent Nine Planets site, is devoted to the big blue marble we call home.
Earth is fifteen percent silicon by mass.
Matt has done a great job mining the geography vein. The site is neatly assembled and includes nice extra resources such as a newsletter, message boards and a bookstore. Click on the icons superimposed on the world map for short news items of significant natural events like earthquakes, floods and landslides that have occurred around the globe. From the native Ainu of Northern Japan to the Shona-speaking people of Zimbabwe, the page promotes and explains native place names, boundaries and cultural history. For a sobering overview of the state of the planet, from the effects of global warming to the growing population, visit this offshoot of the United Nations CyberSchoolBus.