On 14th March (or using USA date style - 3/14) we celebrate everybody’s favorite transcendental number Pi (symbolised by the Greek letter π). Pi = 3.1415926535… , and is the ratio of the circumference of a circle to its diameter. Pi has been worked out to more than 200,000,000,000 digits past the decimal, but as it is an irrational and transcendental number it's exact value can't be calculated. Find out more about Pi on the Pi Credo Topic Page.
The 14th March is also noteworthy as it is Albert Einstein's birthday. Happy birthday Albert!