Witches and skulls take to the streets of many countries this Halloween Wednesday or "Halloween."
The ghosts will fly from the graves, the vampires will leave their sarcophagi full of cobwebs and the aliens, from their saucers.
The monsters, fairies, superheroes and all kinds of costumes that the imagination or the economy allow will also take a walk.RELATED
It is the Halloween party or "Halloween", the well-known American celebration that every year wins more followers worldwide.
Houses decorated in "terrifying" ways, children promising "tricks" to those who do not give candy and meetings of young people and adults until dawn with drinks and masks are only part of one of the best known celebrations today.
Actually, the origins of the tradition are lost in time and mixed with a little religion, a lot of paganism and a lot – a lot – fear (really none, but it's Halloween, so a dose of scare is not over ).
These are some keys for you to understand what is behind the "terrifying" celebration and its history.
Why is it called Halloween?
The roots of Halloween are not really in the United States, but in the United Kingdom.
Its name comes from an English phrase "All Hallows' Eve", which would translate as the eve of all saints.
The Catholic Church instituted as one of its celebrations the "Day of all saints", in honor of those who "enjoy eternal life in the presence of God" and who do not appear in saints or their name is unknown.
Bonfires are another symbol of the celebration. Photo: GETTY IMAGES, via BBC Mundo
Until the 16th century, the night before this celebration there was a vespers service and hence the name of the celebration.
How did it become a 'scary day'?
18th-century historians had already linked Halloween to an ancient pagan festival: a Celtic ritual called Samhain that celebrated the end of summer and the arrival of the short, cold days of autumn.
Samhain lasted three days and began on October 31.
According to some academics, it was a tribute to the "King of the Dead."
The celebration is associated with an ancient pagan cult. Photo: Getty images, via BBC Mundo
More recent studies established that bonfires and a celebration of good harvests were also characteristic of the pagan celebration.
But this theory is based on little evidence and some historians have pointed out that the celebration was changing from region to region, from country to country and, between mute and mute, even altered its meaning.
In the eighth century, there was a turning point: Pope Gregory III changed the original date of "All Saints' Day" from May 13 to November 1.
It is not clear if the movement, which also made the religious celebration obligatory for all Catholics, was an attempt to "Christianize" Samhain.
The truth is that this movement united both celebrations and mixed pagan and Christian traditions.
When did Halloween become the celebration we know now?
It took shape between 1500 and 1800.
The fires were very popular then: they were used to burn the straw (remember that Samhain celebrated the end of the harvest season), but also as a ritual to "repel" witchcraft and disease.
Another tradition was the futurology and divination exercises: people predicted the name of future partners and even the date they would die.
Those rituals of divination took many different forms.
Pumpkins became part of the celebrations in the United States. Photo: EPA, via BBC Mundo
A cabbage extracted from the ground could give clues about the work or personality of the future partner. They also "read" the nutshells.
Food was an important component of the celebrations and one of the most characteristic habits involved children who went from house to house singing rhymes or praying for the souls of the dead.
In return, they obtained cakes that represented the liberation of a soul from purgatory.
How did the celebration come to the United States?
During the Great Famine (1845-49) in Ireland, which was then part of the United Kingdom of Great Britain and Ireland, more than one million people emigrated to the United States.
They took their history and traditions with them, and it is no coincidence that the first mentions of Halloween on American territory appeared shortly after that exodus.
In 1870, for example, a women's magazine published an article that described Halloween as an "English holiday."
Corn and scarecrows are also part of the tradition. Photo: GETTY IMAGES, via BBC Mundo
Initially, the American version was very similar to that of the British countryside.
But there were some crucial additions, such as the introduction of scarecrows in decorations: corn was a crucial crop in American agriculture.
There were others, such as the classic "treat or trick" phrase of children or the use of pumpkins (the British tradition was carving turnips).
According to some historians, the celebration was booming after World War II, when food rationing ended.
What about modern Halloween?
Today, Halloween is the largest non-religious holiday in the United States: in fact, it surpassed Valentine's Day and Holy Week as the peak period for chocolate sales in 2010.
Over the years, it has been exported to other countries, many of them in Latin America.
But it has also had its rough moments and not just for costumes.
In 1964, Helen Pfeil, an American housewife, gifted poisoned candies to children she considered "too old for the game."
The celebration has been exported to many countries. Photo: Getty images, via BBC Mundo
Fortunately, there were no victims, but the episode was the genesis of several urban legends about "contaminated goodies" that lasts until today.
Thus, although it has changed, much over the centuries, Halloween is still a celebration that provides a space for adults and children to play with their fears and fantasies and make fun of them.
It allows a brief respite from social norms that inhibit contact between strangers and unites religion, nature, death and romance.
That is probably why it is so popular.