The Physicist Who Turned Pi Into the World’s Strangest Holiday
The Man Behind the First Pi Day
Larry Shaw didn’t set out to invent a holiday. In 1988, working as a physicist and curator at San Francisco’s Exploratorium, he floated an idea at a staff retreat: celebrate pi. Not abstractly — with actual fruit pies, served at precisely 1:59 p.m., the three digits that follow 3.14. The museum said yes.
From there, Shaw organized what became an annual ritual. Staff and visitors formed “pi-rades,” single-file processions circling the building, each participant representing a successive digit of pi. Shaw led them himself every year until his death in 2017. The Exploratorium never stopped. Today the lineup includes lectures, live concerts, pi processions, and — always — pie.
How Universities One-Upped Each Other
Once Pi Day had a foothold, schools got competitive. St. Bonaventure University schedules its celebration to the minute: festivities begin at 1:59 p.m. on March 14 and run for exactly 2 hours and 65 minutes, encoding 3.14159265 into the event’s duration. Nerdy in the best possible way.
MIT turned admissions into a pi stunt. The university drops undergraduate decisions on March 14 every year, with timestamps engineered for maximum math content. In 2012, the release hit at 6:28 p.m. — a nod to tau, which equals 2π. In 2015, it was 9:26 a.m. on 3/14/15, spelling out 3.1415926 across date and time. The math department presumably approved.
Two Scientific Giants, One Shared Date
Princeton has extra reason to mark March 14. Albert Einstein was born on that date in 1879 — in Germany, but Princeton was his home for the last two decades of his life — and the town celebrates accordingly: look-alike contests, pi recitation competitions, pie tastings, walking tours of his favorite spots.
Then there’s the other side of that date. Stephen Hawking died on March 14, 2018, at 76. Two of the most towering scientific minds of their respective centuries, born and taken on the same calendar day, 139 years apart. The coincidence is hard to shake.
The Pizza Angle Nobody Planned For
Pi and pie share only the sound of their names and the circular shape of the thing. That hasn’t stopped businesses from leaning in hard. Every March 14, chains and local restaurants push deals on pizza, pie, and anything else that happens to be round. Past participants have included 7-Eleven, CiCi’s Pizza, and the Honey Baked Ham Company, which committed to the bit harder than anyone asked.
At various points, whole pizzas have sold for $3.14. Any holiday that cuts your pizza bill down to pocket change earns its spot on the calendar.
The Day Congress Got Briefly Nerdy
By 2009, Pi Day had grown large enough to warrant a congressional opinion. On March 12 of that year, the U.S. House of Representatives passed a non-binding resolution supporting “the designation of a Pi Day and its celebration around the world.” The Association for Competitive Technology and the American Chemical Society both backed it, framing the measure as a nudge to push students toward math.
UNESCO followed. March 14 now doubles as the International Day of Mathematics, giving the holiday a global official standing that Larry Shaw, eating pie in San Francisco in 1988, almost certainly never anticipated.
Pi Gets More Than One Birthday
March 14 is the headliner, but pi appears on the calendar more than once for those paying attention. Pi Approximation Day falls on July 22 — written as 22/7 in day/month format, the classic fractional stand-in for pi. November 10 gets a quieter acknowledgment: it’s the 314th day of non-leap years.
June 28 belongs to tau. Tau is the ratio of a circle’s circumference to its radius, double pi, or roughly 6.28. Tau devotees celebrate with double portions of dessert, which is the correct way to honor a number twice as large as its more famous cousin.
