Pi was first applied to the third month, 14th day of the year by a physicist at the San Francisco Exploratorium in 1988, according to NASA. U.S. Congress declared March 14 National Pi Day in 2009.

On Pi Day, the restaurant offers pizzas for $3.14 each plus tax when you bring in a canned good. Cruz said they would be preparing 1,500 pizza doughs.

Move over, salami and brie—Pizza Hut is taking charcuterie to the next level just in time for Pi Day (3.14). Introducing Pizza Charcuterie, a customizable, Instagram-worthy pizza board designed for ...

Regardless, though, of whether you're here for the math or here for the dessert, here are 14 ideas for your Pi Day Instagram captions: 1. "A cherry pie is . . . ephemeral.