This online atlas created by National Geographic has an impressive selection of maps that chart everything from physical typography and political leanings to climate and population trends worldwide. You can find street maps for all of the United States, Canada and Europe by clicking on â€œStreet Mapsâ€? on the left-hand column of the homepage. The â€œFlags and Factsâ€? link leads you to detailed profiles of 191 countries, which include a brief history of each locale, its demographics, economics and politics â€” and, of course, maps. Follow the â€œWorld Themesâ€? link to view time zones, transportation density and weather maps. Under â€œU.S. Themes,â€? you will find diversity, density and population maps based on Census 2000 data. More specific Census insight is not yet available for 2000, but click on â€œCensus: Population (1990)â€? to see the U.S. mapped by almost any variable. Want to see a map detailing the percentage of people working at home in 1990? No problem. The Web site even has a link to an interactive map of Mars, though that one, of course, has significantly less demographic detail.