National Pi Day — 14 March

To learn about pi, we need to go back a few thousand years and learn about this elusive number. The value of pi was first calculated by Archimedes of Syracuse (287–212 BC), one of the greatest mathematicians of the ancient world.

However, it was first baptized with the Greek letter as its name when William Oughtred called it as such in his works dating back to 1647, later embraced by the scientific community when Leonhard Euler used the symbol in 1737.

But how did Pi Day end up in a country-wide phenomenon? For that, we need to travel to the Exploratorium in 1988 San Francisco, where it was thought up by physicist Larry Shaw.

Shaw linked March 14 with the first digits of pi (3.14) in order to organize a special day to bond the Exploratorium staff together, where he offered fruit pies and tea to everyone starting at 1:59 pm, the following three digits of the value. A few years later, after Larry’s daughter, Sara, remarked that the special date was also the birthday of Albert Einstein, they started celebrating the life of the world-famous scientist.

Pi Day became an annual Exploratorium tradition that still goes on today, and it didn’t take long for the idea to grow exponentially, hitting a peak on March 12, 2009, when the U.S Congress declared it a national holiday.

Now, celebrated by math geeks all around the circumference of the world, Pi Day became a pop culture phenomenon, with several places partaking in the activities, antics, observations and all the pie eating they can.