I confess that "a billion" seems a bit abstract for me.
Here are some ways to put it into perspective:
- a billion seconds ago it was 1972
- a billion minutes ago it was A.D. 102
- a billion hours ago it was the "Stone Age"
- If all of Saddam's $21 billion were in dollar bills and you wanted to count them (at a rate of $1 per second), it would take you 665 years, 332 days of continuous counting.
- Let's say that you made a book, and on every page you printed 1000 dollar signs on every page. If the book contained 21 billion dollar signs, it would be 21 million pages long, 42 million inches thick, and would be the length of 11.5 football fields placed end-to-end.