For most Americans, the last day of October is a time of trick-or-treating, costumes, candy, and various spooky things from horror movies to haunted houses.
Halloween, the holiday most known for its playful scaring and bags of sweets, is most closely associated by mainstream culture with Oct. 31.
However, for hundreds of churches across the United States and many others throughout global Protestantism, Oct. 31 is a time to remember the birth of the Reformation.
Known as Reformation Day, many churches hold special services either on the day itself or the nearest Sunday, which this year was Oct. 30.
Below in no particular order are five facts about the observance, history, and celebrations scheduled for next year, the 500th anniversary of the Reformation.
1. 95 Theses
Reformation Day marks the anniversary of when Augustinian monk Martin Luther nailed 95 theses, or questions and propositions for debate, to a church door in Wittenberg, located in modern day Germany.
Luther took issue with the Roman Catholic Church's teaching that salvation came through faith and good works rather than faith alone.
Also a concern for him was the widespread practice of indulgences, in which people gave money to the Church in return for forgiveness of sins.
"The 95 Theses were quickly distributed throughout Germany and then made their way to Rome. In 1518, Luther was summoned to Augsburg, a city in southern Germany, to defend his opinions before an imperial diet (assembly)," noted History.
"A debate lasting three days between Luther and Cardinal Thomas Cajetan produced no agreement. Cajetan defended the Church's use of indulgences, but Luther refused to recant and returned to Wittenberg."
Soon enough, the movement spread throughout Europe, causing both violent upheaval, sweeping cultural change, and theological debates that continue to the present day.
2. Varied dates
While Luther's specific act that began the Reformation took place on Oct. 31, 1517, celebrations commemorating the action were not always performed and the dates do vary.
"Officially, Reformation Day has been commemorated since 1567. Exact dates for the holiday varied until after the 200th celebration in 1717 when Oct. 31 became the official date of celebration in Germany and later expanded internationally," noted Got Questions.
"Within the Lutheran tradition, Reformation Day is considered a lesser holiday and is officially named 'The Festival of the Reformation.' Most Lutheran churches (and others who celebrate this day) commemorate it on the Sunday prior to Oct. 31."
3. Different ways to celebrate
So how does one celebrate Reformation Day exactly? Worship is the most obvious way of doing so, with congregations offering services either on the Oct. 31 or the Sunday before.
Tom Macy, senior pastor at Faith Church in Indianapolis, Indiana, told The Christian Post in a 2013 interview that his congregation had a Reformation-themed service, which included singing Luther's most famous hymn, "A Mighty Fortress is Our God."
"I often find an appropriate connection to acknowledge the importance of the Reformation as a return to biblical faithfulness," said Macy.
"This Sunday, I am in 1 Corinthians 10:1-13 with the focus on temptation. No problem to find a connection to Luther's battle with temptation as expressed in 'A Mighty Fortress: And though this world with devils filled, should threaten to undo us,'" he told CP.
Pastor Skip Athey of Grace & Truth Family Baptist Church in Plant City, Florida, told CP in an earlier interview of the various festivities his congregation oversaw on Reformation Day.
"As part of our celebration we have families do brief reports on the lives of the Reformers, men like Martin Luther, John Calvin, and Ulrich Zwingli," said Athey.
"We dress up in costumes of that period and have games for the children, such as Pin the Thesis to the Door, and have lots of good food and music."
4. Martin Luther Square
In his own lifetime, Luther's relationship with the Catholic Church was not exactly amiable. Indeed, in 1521 the Church excommunicated the German monk for his writings.
However, centuries later the Church seems to have mellowed on their sentiments, as a recent project to name a square in Rome after the Protestant Reformer received the blessing of none other than Vatican City itself.
According to an August 2015 story from the National Catholic Reporter, a hilltop square near the Colosseum was named the Piazza Martin Lutero.
"The move has been six years in the making, following a request made by the Seventh-day Adventists, a Protestant denomination," reported NCR.
"The original plan was to inaugurate the square in time for the 500th anniversary of Luther's historic trip to Rome in 2010."
Far from opposing the move, the Reporter quoted a statement from Vatican spokesman the Rev. Ciro Benedettini expressing support for the naming of the square.
"It's a decision taken by Rome city hall which is favorable to Catholics in that it's in line with the path of dialogue started with the ecumenical council," said Benedettini.
5. Nearly 500 years old
Next year will mark the quincentennial anniversary of when Luther nailed the 95 Theses to the church door and many are preparing many ways to observe the milestone.
Since 2008, a tourist project in Thuringia has been overseeing the "Luther Decade," which puts an emphasis on sites within the German province that were relevant to the life of the Protestant leader.
"Although Martin Luther nailed his famous theses to the door of the church in Wittenberg, Saxony-Anhalt, it is not possible to ignore Thuringia when considering Luther's life," noted their website.
"It was here that he became a monk, translated the Bible into German and the place where the Schmalkaldic Articles were created, the most important basis of Evangelical Lutheran belief."
"The Luther Decade" includes different themes for the years 2008 to 2017.
"Authority and responsibility, belief and power, freedom of conscience and human rights — these are themes of the Reformation which are also present today and deserve an in-depth discussion in the church and in society," reads the site Luther in Thueringen.
For its part, the Luther Church–Missouri Synod has been preparing a plethora of things for the milestone, including web resources, special worship services, outreach grants, and a documentary.
"Sinners still need Jesus, only Jesus — that's really the point Luther was making with the 95 Theses. He was fundamentally concerned about pastoral care for God's sheep," said LCMS spokesman the Rev. Randall Golter in a statement last year.
"We must remember this celebration is not only for our ears but for those who do not know Jesus; our celebrations need an outward push to others, which is our Lord's tendency always."