Some teacher direction would most likely be needed, depending upon the class. This site is not browser specific and requires no plugins. It displays a world map. Students can click on the continents to access more specific maps. They are colorful, clear, well labeled, and can be enlarged.
Relief maps are also accessible.
These maps could be used in a discussion incorporating geographic terms. Maps can be downloaded and printed. This site is not browser specific and no plugins required. This colorful site uses dinosaurs to give students tips on how they can take care of the earth. The reading and factual material is grade appropriate.