Breathing Earth. 200 Years of History in 4 Minutes. Tree of Life. Rice = People. Of All The People In All The World, a traveling art exhibit in the UK, uses grains of rice to bring the large numbers behind world populations to the grasp of the average human being.
In the exhibit, one grain of rice equals one person and those grains of rice are put together to represent all kind of statistics from the small (such as the number of people who have walked on the moon) to the large (the population of the United States as seen below). Link.