Why Is Pi Day a Thing?
The concept of Pi is thousands of years old, but the holiday is relatively new. In 1988, physicist Larry Shaw cooked up the idea of Pi Day when he organized the first celebration with his coworkers at the San Francisco Exploratorium. Shaw and his cohort honored π by tucking into fruit pies on March 14th.
It immediately became a tradition that the San Francisco Exploratorium shared with the public and expanded to include various attractions such as a pi shrine, parades, and singing. In 2009, the US House of Representatives officially recognized Pi Day as a national holiday, and in 2019 UNESCO declared March 14th the International Day of Mathematics.