The Entire Universe in Scale.

Have you ever wondered how big an atom is compared to say... a Boeing 747?  This interative display is certainly for you.  Created by Cary Huang this is a sliding scale that takes you in a few seconds from the smallest length possible (Planck Length) 0.00000000000000000000000000000000001m (10-35 m) to the estimated size of the universe itself - 93,000,000,000 light years.

http://primaxstudio.com/stuff/scale_of_universe/

This is a must see, although be warned, it may leave you feeling ever so slightly small and insignificant when it comes to the size of the rest of existance.