Deeply rooted in the cultures around the world, 7 is simply a practical number that makes life easier for all of us. Since George A. Miller, a respected professor of psychology at Princeton University, introduced his theory of “The Magical Number 7” in 1956: our short-term memory is generally considered to have the capacity for around 7 elements. While some scientists may speak of even less than 7, what this really means is that the average human (children included) can remember 7 digits, letters, words, or other units with just a little brainwork. This small effort is what solidifies it in our memory. So a system of 7 elements, such as The Official New 7 Wonders of the World, is something that every human can follow and remember by challenging his or her brain a little bit.