On March 14 (3/14) we celebrate Pi Day since 3, 1, and 4 are the first three significant digits of Pi. It's also the day we eat lots of pies. You may wonder why, but you see, Pi is circumference over diameter, that happens to be a constant in every circle.
History of Pi Day
In 1988 at the San Francisco Exploratorium, Pi Day was celebrated on a larger scale. It was organized by Larry Shaw, a physicist. The staff and the public gathered around one of the exploratorium's circular spaces for marching as well as eating fruit pies.
In 2009, on March 12, the U.S. House of Representatives passed a non-binding resolution and made March 14, as National Pi Day. In 2010 Google Doodle was celebrating the day with images of circles and pi symbols.
In 2015, Pi Day had a special significance, as 3/14/15 at 9:26:53 a.m and also p.m, the date and time representing the first 10 digits of Pi.
How to celebrate Pi Day
Simple, by eating lots of Pies!