A tightly-packed stack of new $1,000 bills totaling $1 billion would be 63 miles high. In comparison, jet planes fly at 30,000 - 40,000 feet (5.7 - 7.7 miles high).
About a billion minutes ago, the Roman Empire was in full swing. (One billion minutes is about 1,900 years.)
About a billion hours ago, we were living in the Stone Age. (One billion hours is about 114,000 years.)
About a billion months ago, dinosaurs walked the earth. (One billion months is about 82 million years.)
A billion inches is 15,783 miles, more than halfway around the earth (circumference).