You are using an older browser version. Please use a supported version for the best MSN experience.

What Is Pi Day? Mathematical Constant Celebrated Annually On March 14

March 14 is Pi Day, a day which honors the mathematical constant π. Pi Day was first celebrated in 1988 at the San Francisco Exploratorium. Revelers ate pie during the celebrations, sparking the annual tradition.

Latest Videos

Featured Channel: Viral Videos

Featured Partners

image beaconimage beaconimage beacon