The 150-year-old periscope-like lens at the top of the Outlook Tower throws an image of nearby streets and buildings onto a circular table, and the moving "picture" can be magically magnified with just a bit of cardboard. Guides reveal this trick, help to identify landmarks, and discuss highlights of Edinburgh's history. In addition, the observation deck offers free telescopes, and there are several exhibits in the "World of Illusions" with an optical theme that will keep some children occupied. The last camera presentation begins 1 hour before closing.