It’s March 14, 2016, which also means today’s date matches the first three numbers of the ratio of a circle’s circumference to its diameter - 3.14159265359 or 3.14 for short. Although last year’s date 3/14/2015 perfectly matched the first four digits of Pi, some math enthusiasts are calling this year the “Rounded Up Pi Day.”

What’s so special about this number and how was it first discovered?

First off, the number seems never ending for us non-mathematicians. In fact, computer scientists have calculated billions of digits of pi and it still continues all the way to infinity. This mathematical number was first calculated about 4,000 years ago by Greek mathematician and inventor Archimedes of Syracuse, to measure circular objects. The Greek symbol π was first used by William Jones in 1706 and was popularized by Leonhard Euler, who adopted it in 1737.

So, that’s the short version of the history of Pi. In celebration of the mathematical number, here are some great Pi Day deals you can find in these cities: New York, Chicago and San Francisco.