In general humans tend to think at a very local scale. They can visualize the things that directly impact their lives, like how much they spend on groceries or rent. But as numbers grow beyond that local human scale they become increasingly abstract and hard to get your head around. How big is 93,000,000 (roughly the number of miles to the Sun) or $8,822,366,610,275 (the current amount of the US National debt)? In isolation they don't mean much.
Visual representations can more readily give a sense of scale to huge numbers. Artist Chris Jordan has created a series of images that provide some sense of visual scale to the numbers that represent our consumption patterns. The image of Mt. Denali is comprised of 24,000 GMC
Denali logos, equivalent to six weeks of sales of the SUV in 2004. There are more striking images at Chris' website.
[source: Chris Jordan via Gizmodo