The history of kissing
For instance, in Naples in 1562 kissing publicly was punishable by death.
The word "kiss" comes from the Germanic word kussjan, probably because of the sounds it makes.
In a lifetime the average person spends around 336 hours kissing - equivalent to a fortnight-long snog, reports a major newspaper.
What we term a French kiss is known as an English kiss in India.
As kisses weren't shown in Indian cinema for many years, the first open-mouthed smooch they saw was in a little-known English-language film in 1926.
Meanwhile the French describe tongue kissing as "rouler une pelle" - "to roll a shovel" - or "rouler un patin" - "to skate".
The 2005 film Brokeback Mountain drew a lot of attention for depicting a sexual relationship between men, but the first all-male kiss in a film came almost 80 years earlier, in the 1927 movie Wings.
However the first openly gay big-screen kiss came even earlier - as the 1922 movie Manslaughter included two lesbians snogging.
The most kisses seen in a film was 191 - Don Juan, in 1926 - while the longest-ever kiss lasted a breathtaking (and strength-sapping) 31 hours and 30 minutes.
In 1990 Alfred Wolfram kissed 8,001 people in eight hours during a festival in Minnesota - an average of 16 people per minute.
But kissers should beware as a single snog can contain up to 278 types of bacteria, some of which may carry diseases, while a passionate peck can raise hormone levels enough to shorten your life by a full minute.