For those of us on the Imperial measurement system here is something that helps visualize what metric measurement is... 1 millimeter is roughly twice the width of the lead of a mechanical pencil. 1 cenimeter is roughly the thickness of a piece of sliced bread. 1 meter is about 3 inches longer than a yard. 1 kilometer is almost 2/3rds of a mile. 1 kilogram equals 2.205 pounds. When rough estimating is necessary this is a quick reference that always helps me.