Each year, starting from Dec. 16 until Christmas Eve, thousands of people in the United States and Central America participate in "Las Posadas," a centuries-old tradition that retells the story of Mary and Joseph's travels from Nazareth to Bethlehem, seeking some sort of shelter.

In Spanish, "posadas" translates to "lodging."

The tradition dates back to Spain more than 400 years ago, according to the Catholic website Franciscan Media. 

It made its way to Central America with the arrival of the Spanish, and has been observed as a key part of Mexican and Mexican-American Christmas celebrations since. 

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"The tradition of Las Posadas comes from the desire of devout believers to commemorate a very specific moment found in the Gospels — ‘because there was no room for them in the inn,'" said Fr. Matthew Zuberbueler, pastor of St. Anthony Catholic Church in Falls Church, Virginia, told Fox News Digital. 

During the nine nights of Las Posadas, two people dress in costume as Mary and Joseph. 

They're sometimes joined by people dressed as other figures from the nativity story in the Bible, such as angels and shepherds. 

two children in costume in crowd

Two children dressed as Mary and Joseph (in front) are joined by their church community in a celebration of Las Posadas. (St. Anthony of Padua Catholic Church)

"Accompanying Joseph and Mary — who is soon expecting the birth of her son, Jesus — on their arduous journey to Bethlehem, people young and old find the space in their hearts and homes to make the holy visitors welcome," Zuberbueler said. 

In a candlelit procession, the group travels to different places — meant to symbolize inns — and get turned away, as Mary and Joseph were. 

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The inns "can be different houses, but at our church, we just use our various church buildings," Ani Gonzalez, director of music at a Catholic parish in the Houston area, told Fox News Digital. 

crowd praying during las posadas

Las Posadas dates back centuries, and is an important part of many Mexican Christmas celebrations. (St. Anthony of Padua Catholic Church)

The group sings songs and recites prayers, begging to be let inside for shelter for the night. 

Each time, they are greeted by the slamming of a door by the person playing the role of innkeeper.

"At the time of the first Christmas — like now — welcoming the Savior turns less-than-ideal surroundings and circumstances into opportunities for peace," said Zuberbueler. 

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Eventually, Mary and Joseph are allowed to enter the final "inn," where there's a celebration, said Gonzalez. 

"There’s always pan dulce, or tamales or posole or whatever that group feels like making — champurrado, ponche, chocolate, atole," she said.

children dressed as angels

Children typically dress as angels and shepherds as part of the nine-day Las Posadas tradition.  (Mario Tama/Getty Images)

The festivities also include a pinata, said Gonzalez. 

"Traditionally, it's the star-shaped kind," she told Fox News Digital. 

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This process repeats each night until Christmas Eve. Many churches celebrate Midnight Mass following Las Posadas on Christmas Eve. 

At Gonzalez's parish, the yearly Las Posadas brings the entire church together. 

"We have a different group sponsor it every night," she said. "The Guadalupanos, the CCE kids, the mother's group, etc." 

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For Gonzalez's community, and for many of Mexican heritage in the United States, Las Posadas "is a really important part of Christmastime." 

Others "go look at Christmas lights, or go listen to 'Handel's Messiah' or watch ‘The Nutcracker,’" said Gonzalez. 

"And Mexicans do Las Posadas." 

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