Actually there are only 19 but you get the idea.
Visualizing huge numbers can be very difficult. People regularly talk about millions of miles, billions of bytes, or trillions of dollars, yet it’s still hard to grasp just how much a “billion” really is. The MegaPenny Project aims to help by taking one small everyday item, the U.S. penny, and building on that to answer the question: “What would a billion (or a trillion) pennies look like?”
The Feynman Lectures on Physics as pdf and mp3s.
My dad did two tours of duty in Vietnam. While there he took photos and sent home slides so that his wife and son could see him. We’d look at these slides nearly every night. I will hopefully get some comments for each one from my dad.