Tuesday was the first day of a 10-day stretch of palindrome dates — at least, in the United States.  A palindrome is typically a word, such as the name Bob, that reads the same backward and forward. With dates, it occurs when the numerical signature of the day is symmetrical in the same way.

Because dates are formatted differently from country to country, not all dates that are palindromic in one format are palindrome days in another. In the United States, dates are generally expressed by month first, then day, then year. But many countries write the day first, then the month, then the year.

Tuesday was Sept. 10, 2019, which in the U.S. is written 9-10-19. Turn that around and look at it again: it’s 91019 either way.

That same pattern will hold true for the next 10 days:

    • 9-10-19
    • 9-11-19
    • 9-12-19
    • 9-13-19
    • 9-14-19
    • 9-15-19
    • 9-16-19
    • 9-17-19
    • 9-18-19
    • 9-19-19

Ten-day Palindrome stretches are not that rare, according to Time and Date.

We’ve had a similar stretch every year since 2011, when it first occurred from Jan. 10 (1-10-11) to Jan. 19 (1-19-11). In 2012, the same sequence of dates occurred in February, and so on.

Correction:This story has been updated to remove an assertion that we’re in the midst of our last 10-day stretch of palindrome dates (e.g. 9-11-19) in the 21st century. This is not the last 10-day stretch of them in this century. There are more such palindrome dates to enjoy!