Valentine's Day is synonymous with gift giving. Flowers, chocolates and diamonds, if you're lucky, all wrapped in a ribbon and accompanied by a hand written card.

Valentine's Day is one of those rare holidays that is enjoyed by almost everyone in the world. After all, what's not to like about a day when loved ones get to shower each other with cards, flowers, chocolates, and jewelry? This display of affection does come at a steep price — Almost $19 billion, and that number is just for the USA.

But, how did the story begins? The history of Valentine’s Day–and the story of its patron saint–is shrouded in mystery. We do know that February has long been celebrated as a month of romance, and that St. Valentine’s Day, as we know it today, contains vestiges of both Christian and ancient Roman tradition. But who was Saint Valentine, and how did he become associated with this ancient rite?

The Catholic Church recognizes at least three different saints named Valentine or Valentinus, all of whom were martyred. One legend contends that Valentine was a priest who served during the third century in Rome. When Emperor Claudius II decided that single men made better soldiers than those with wives and families, he outlawed marriage for young men. Valentine, realizing the injustice of the decree, defied Claudius and continued to perform marriages for young lovers in secret. When Valentine’s actions were discovered, Claudius ordered that he be put to death.

There are many stories behind it.

The Pope, of course, was not the one who transformed it into a commercial holiday. That credit goes to Richard Cadbury, a member of the famous British chocolate company, and Massachusetts businesswoman Esther Howland. The former came up with the brilliant idea of selling bite-sized chocolates packaged in heart-shaped boxes while Howland popularized handmade lace paper Valentine cards that featured messages of love.

With over 145 million cards exchanged in the US and over a billion worldwide, Valentine's Day is one the biggest moneymakers for greeting card companies. It is second only to Christmas when 2.6 billion cards are sold. It is no wonder that the holiday is sometimes referred to as a 'Hallmark Holiday.' Surprisingly, though, a majority of the cards are purchased for teachers and children!

Flowers are also very popular. About 51% of people, primarily men buy red roses for their loved ones. At inflated prices, this adds up to 1.9 billion USD! Almost 35% of Americans that celebrate the holiday treat their loved ones to a special meal. This 'splurge' costs an astounding $3.6 billion USD. This day is a very healthy day for those who are in love.