Secret Worlds: The Universe Within - View the Milky Way at 10 million light years from the Earth. Then move through space towards the Earth in successive orders of magnitude until you reach a tall oak tree just outside the buildings of the National High Magnetic Field Laboratory in Tallahassee, Florida. After that, begin to move from the actual size of a leaf into a microscopic world that reveals leaf cell walls, the cell nucleus, chromatin, DNA and finally, into the subatomic universe of electrons and protons.
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html