It took place at exactly 1:59 p.m., which are the numbers that follow 3.14 in Pi, and, after the march, Shaw and his wife set up fruit pies for the workers to eat.

It took place at exactly 1:59 p.m., which are the numbers that follow 3.14 in Pi, and, after the march, Shaw and his wife set up fruit pies for the workers to eat. Sara Shaw said for the first ...

Here's what to know. SAN FRANCISCO -- Every March 14, mathematicians, scientists and math lovers around the world celebrate Pi Day, a commemoration of the mathematical sign Pi.