Google Earth provides a stunning visual, and I must say "educational" experience, by bringing together the best of its recently acquired Keyhole satellite-imaging technology with its own local search and mapping capabilities.
Click image to enlarge it
Google Earth is a standalone Windows application that's essentially an enhanced and upgraded version of Google Keyhole product.
Google Earth can in fact make anyone into a virtual bird capable of flying over Canada, the U.K., 38 major cities in different countries of the world and, all over the US.