Tuesday, Jan. 19, 2021 may be widely known as the day before Inauguration Day, but it's also marked off on calendars across the US as National Popcorn Day. 

Some companies, such as Cinemark Holdings, Inc. and its movie theaters, are observing the day with specials. Cinemark's week-long Cinemark Popcorn Fest, held from Monday, January 18 until Sunday, January 24, gives guests $2 off any size popcorn at all Cinemark theaters serving concessions.

In addition to the week-long deal, Cinemark is celebrating the start of 2021 by giving 21 Cinemark moviegoers free popcorn for a year.

Click here for more on the special. 

The special is all about appreciation of the type of corn called Zea mays everta. 

This particular corn, not the kind that you'll typically see on a dinner plate, has small ears, and its kernels burst when exposed to dry heat. 

In 1948, small heads of Zea mays everta were discovered in the Bat Cave of west central New Mexico and the oldest ears of corn in that cave were determined to be about 4,000 years old. Several individually popped kernels were also found, which have since been carbon dated and shown to be approximately 5,600 years old. Archeologists have also unearthed evidence of early use of popcorn in Peru, Mexico, and Guatemala, as well as other places in Central and South America. 

Aztecs used popcorn to decorate their clothes, create ceremonial embellishments, and also for nourishment. Native Americans have also been found to eat and use popcorn in their daily lives. Eventually, as colonists moved around North America, and the land became known as the USA,