Halloween is a spooky holiday that is celebrated by millions of Americans each year. The official date of Halloween is October 31, but Halloween parties are often held on other days toward the end of October. Many TV stations air scary Halloween-themed movies throughout the month of October.

Halloween is known for its costumes, pumpkin carving, trick-or-treating, scary movies, and festive parties. There are aspects like hayrides and bobbing for apples which celebrate the harvest period, and many others which embrace the creepy superstitions of witches and monsters, ghosts and ghouls.

Though most Americans know about these common holiday traditions, there are many lesser-known interesting and fun facts about Halloween. Here are five:

That's a lot of candy

According to the National Retail Federation, Halloween retail sales are estimated to be around $5 billion. They estimate that two-thirds of Americans make Halloween retail purchases, such as costumes, decorations, and candy. While that sounds like a lot of money, it falls behind the collective winter holidays (over $450 billion), Mother’s Day (over $13 billion), Valentine’s Day (over $13 billion), Easter (over $12 billion), and Father’s Day (over $9 billion).

Costumes by ranking

Each September, the National Retail Federation publishes a survey, conducted by BIGresearch, which lists the top Halloween costumes planned for that year. The survey includes costumes for adults, kids, and pets. For kids, princess costumes have topped the list for several years. Witches and pirates are common favorites for both kids and adults, and pets are frequently dressed as pumpkins, devils, or witches.

Where does trick-or-treating come from?

Trick-or-treating has roots in multiple cultural traditions. Ancient Celts had a tradition of putting out food and treats on All Hallows Eve, the night before Samhain, to please the spirits that walked among the living that night. During medieval times, there was a Christian tradition of “souling” on November 1, or All Saints Day, where poor people would go door to door offering prayers for the dead in exchange for “soul cakes.”

So...why pumpkins?

Pumpkins celebrate the harvest elements of Halloween. When carved into jack-o’-lanterns, they also embrace the holiday’s spookier side. Pumpkins come in many sizes, and 10 to 12 pounds is considered average. Yet each year, many growers compete to grow the largest giant pumpkin. In 2010, Guinness officials certified that Chris Stevens of New Richmond, Wisconsin, had grown the world’s heaviest pumpkin at 1,810 pounds!

Most popular treats

When it comes to candy, the National Confectioners Association’s 2009 Halloween Survey shows that adults and kids are both fans of the holiday. Nearly one in five adults surveyed said that Halloween without candy was a scary idea, and nearly 30 percent admitted plans to take at least a handful from the treat bowl for themselves. Among those who give out candy, chocolate is the most popular, followed by lollipops and hard candy, chewing or bubble gum, and caramel treats.