I've always loved looking through microscopes. Inner space is just as vast and mysterious and gorgeous as outer space (I remember first realizing this when I saw the amazing Powers of 10 film in 6th grade. Plus, my sister and I had our own microscope, and we were always blown away by how luminous and textural a single strand of hair looked when it was magnified.)
Nikon has sponsored a Small World Photo Contest, for photos taken through microscopes. Above, you'll see a frog cell and a grape. There are dozens of other incredible, radiant photos at the site.