The 2 tiny people, and their 2 tiny shadows make the whole dam look huge. You probably remember your highschool physics teacher explain: "if the nucleus of an atom is a strawberry, its electrons would be flying around the football field".
Something to think about when making your next slide composition. Image purchased from iStockPhoto
UPDATE: I have now added a chart concept featuring a dam in the SlideMagic template store, you can download it here.