July 6 is International Kissing Day, and whether you kiss the ones you love or kiss token for good luck, here are 11 facts you might not know about that peck from your lips.

1. KISSING IS GOOD FOR YOU.

A few of its benefits: it can help reduce dermatitis and blemishes. It can also help fight tooth decay because the extra saliva it produces cleans out your mouth. Kissing for a minute can burn up to 26 calories. And when practiced regularly, kissing may even add a few years to your life. One study claimed that men who kiss their wives every morning before leaving for work live five years longer than those who don't.

2. ON THE OTHER HAND, KISSING CAN SPREAD GERMS.

One peck can contain up to 80 million new bacteria, and frequent kissing can change your microbiome. But emerging research suggests that sharing microbes could offer some healthy benefits.

3. WE SPEND TWO WEEKS OF OUR LIVES KISSING.

On average, people spend about 336 hours snogging—that’s a lot of lip service.

4. THE LONGEST MOVIE KISS LASTED MORE THAN THREE MINUTES.

Actresses Necar Zadegan and Traci Dinwiddie locked lips for a record-setting three minutes and 23 seconds in the 2010 film Elena Undone. (Actors Gregory Smith and Stephanie Sherrin’s smooch lasted for six minutes in the 2005 low-budget comedy Kids in America, but it took place during the closing credits.)

5. THE LONGEST REAL-WORLD KISS LASTED A LOT LONGER.

In 2013, Thai couple Ekkachai and Laksana Tiranarat smashed their previous world record of 46 hours, 24 minutes and 9 seconds, set in 2011. They kissed without a break for an incredible 58 hours, 35 minutes and 58 seconds, which beat the existing record (held by another Thai couple) by almost eight hours.

6. ARCANE LAWS ABOUT KISSING ARE STILL ON THE BOOKS.

In Indiana it is illegal for men with mustaches "to habitually kiss human beings." Presumably, any other species is fair game. In Colorado’s Logan County, a man is forbidden to kiss a woman while she’s asleep. And in Hartford, Connecticut, men are apparently prohibited from kissing their wives on Sundays.

7. KISSING THE BLARNEY STONE IS OK, THOUGH.

According to legend, the builder of Ireland’s Blarney Castle, one Cormac Laidir MacCarthy, was involved in a lawsuit and appealed to the Irish goddess Clíodna for help. She told him to kiss the first rock he found on his way to court. As a result, he pleaded his case with great eloquence and won. MacCarthy then laid the lucky stone into the parapet of his castle.

8. LIPS ARE LIKE SNOWFLAKES.

As with frosty crystals and human fingerprints, no two lip impressions are the same.

9. A KISS HAS MARKED THE SPOT SINCE THE MIDDLE AGES.

Back in medieval times, before most people could read or write, they signed their name with an x, then kissed the mark to show their sincere intent.

10. FRENCH KISSES ARE IN THE DICTIONARY.

The term "French kiss” has been around since Victorian times, and first appeared in print in a WWI-era book called Private Lindner’s Letters: Censored and Uncensored. The thought was that the French were experts in passionate romance. In France, they call it baiser amoureux (love kiss) or baiser avec la langue (kiss with the tongue). The word galocher, the verb for “to kiss with tongues,” was added to French dictionaries in 2014.

11. A KISS WENT WHERE NO KISS HAD GONE BEFORE.

The first interracial kiss on television was featured in a 1966 episode of Star Trek. Originally, the script called for Spock (Leonard Nimoy) and Lt. Uhura (Nichelle Nichols) to lock lips, but according to Nichols, "Bill Shatner said, 'Oh no! If anyone is going to get to kiss Nichelle, it’s going to be me!' And so they rewrote it and we all laughed about it." Fan mail was overwhelmingly positive, and one particular fan stands out for Nichols. "[Dr. Martin Luther King told me] that I was one of the most important people in his family," she said, "[and] that they watched Star Trek and that I was a role model and their hero."

A version of this article ran in 2016.