02/02/2020: Welcome to international Palindrome Day, first in almost 1000 years

Sunday isn't simply the Superbowl and Groundhog day. It is International Palindrome Day, a day when the date reads the same backwards and forwards.

The last Palindrome day was 909 years ago on November 11, 1111. Also known as 11/11/1111. Using the mm-dd-yyyy format, there are only 12 palindrome days in the entire 21st century.

A Palindrome Day happens when the day's date can be read the same way backward and forward. The dates are similar to word palindromes in that they are symmetrical. 'BOB' is a palindrome.

Some well-known English palindromes are, "Able was I ere I saw Elba",[4] "A man, a plan, a canal – Panama",[5][6] "Madam, I'm Adam" and "Never odd or even".

English palindromes of notable length include mathematician Peter Hilton's "Doc, note: I dissent. A fast never prevents a fatness. I diet on cod" and Scottish poet Alastair Reid's "T. Eliot, top bard, notes putrid tang emanating, is sad; I'd assign it a name: gnat dirt upset on drab pot toilet."

Palindromes date back at least to 79 AD, as a palindrome was found as a graffito at Herculaneum, a city buried by ash in that year. This palindrome, called the Sator Square, consists of a sentence written in Latin: "Sator Arepo Tenet Opera Rotas" ("The sower Arepo holds with effort the wheels"). It is remarkable for the fact that the first letters of each word form the first word, the second letters form the second word, and so forth. Hence, it can be arranged into a word square that reads in four different ways: horizontally or vertically from either top left to bottom right or bottom right to top left. As such, they can be referred to as palindromatic