 On the back of the $1 bill is the Great Seal of the United States. Take a look and notice these few key points. First, it's a picture of a pyramid. Why that structure? Because the pyramid has long been known as a symbol of strength and duration. But look more clearly. The pyramid has 13 levels of stone, one for each of our original 13 states. The Roman numerals on the bottom number 1776, our nation's year of birth.