Are you sitting down? Good. There’s something we want to tell you, and it’s pretty big: Today is Square Root Day. Don’t believe us? We’ll prove it the only way one can … with math:

April 4, 2016 … 4/4/16 … 4*4=16.

Today is pretty special, as we won’t be getting another a Square Root Day until May 5, 2025. After that, you’ll have to wait until June 6, 2036, and after that … well, grab a calculator and figure it out for yourself.

While Square Root Day is a naturally occurring event, we have retired California teacher Ron Gordon to thank for bringing it to everyone’s attention. Gordon came up with the idea for Square Root Day in 1981. He launched a one-man PR campaign and sent press releases to a slew of media outlets in order to drum up coverage for that first Square Root Day (9/9/81). It was a success (you are reading about it in 2016), and Gordon added other mathematically significant days to his repertoire, including “Odd Day” (three odd numbers in a row, i.e. 11/13/15), “Ones Upon a Days” (1/1/11, 11/11/11, etc.), and “Trumpet Day” (2/2/22 … say it out loud and you’ll get it).

On his pun-filled website for Square Root Day, Gordon has some suggestions for how to celebrate:

It's a good day to … get things squared away, try to fit a square peg into a round hole, go square dancing, tie a square knot, travel on Route 66, drink rootbeer from a square glass, root for the underdog, eat a square meal, or watch the pigs root around.

Given that there are only nine Square Root Days each century, Gordon explains why this day is so special while also providing an eloquent examination of our fleeting mortality:

These days are like calendar comets—you wait and wait and wait for them, then they brighten up your day—and poof—they're gone!

That’s a lot to deal with on this Square Root Day. If all this profundity has you feeling down, remember: you can always turn a negative into a positive just by squaring it.