March 14 is known around the world as “Pi Day.” “Pi” is something you may remember from math class. It is the number that results when the distance around a circle is divided by the distance across the circle. It is a very important number in geometry as well as for fields like construction and architecture. Pi is an irrational number. It never ends. But the way it begins is always this: 3.14159. The date March 14, as we write it in the United States, is 3-14. American physicist Larry Shaw started Pi Day back in 1988.