Superstitious people may be looking over their shoulder for signs of trouble today.
It's Friday the 13th. Meaning bad luck or a movie villain in a hockey mask could be right around the corner.
"Very superstitious, writings on the wall. Very superstitious, ladders bout' to fall," Stevie Wonder wrote in his song "Superstition" that was released in 1972.
Others may see it as just another day and proceed as normal.
"When you believe in things that you don't understand, then you suffer. Superstition ain't the way," finishes the chorus of Wonder's song.
Friday the 13th is considered an unlucky day in Western superstition. It occurs when the 13th day of the month in the Gregorian calendar falls on a Friday, which happens at least once every year but can occur up to three times in the same year.
There has already been one Friday the 13th this year. It was on April 13. In 2017, it occurred twice, on January 13 and October 13.
There will also be two Friday the 13ths every year until 2020.
The fear of the number 13 has been given a scientific name: "triskaidekaphobia;" and on analogy to this the fear of Friday the 13th is called paraskevidekatriaphobia, from the Greek words Paraskev meaning "Friday"and dekatres meaning 13.
Research on the origin of the day shows no one is absolutely sure where the idea that Friday the 13th is unlucky originated. Donald Dossey, the founder of the Stress Management Center and Phobia Institute in Asheville, N.C., suspects the fear can be traced back to a Norse myth about 12 gods who had a dinner at Valhalla-the fabled hall where legendary Norse heroes feasted for eternity after they died-that was interrupted by a 13th guest, the evil and mischievous god Loki.
According to legend, Loki tricked another god into shooting his brother with a magical spear tipped with mistletoe. Therefore, the number 13 was branded as unlucky because of this unwanted 13th guest.
In Christianity, Jesus was betrayed by his Apostle Judas who was the 13th guest to arrive for the Last Supper.
Christians have also traditionally been wary of Fridays because Jesus was crucified on a Friday.
According to the Stress Management Center and Phobia Institute, an estimated 17 to 21 million people in the United States are affected by a fear of Friday the 13th, making it the most feared day and date in history. Some people are so paralyzed by fear that they avoid their normal routines in doing business, taking flights or even getting out of bed.
Despite this, representatives for both Delta Air Lines and Continental Airlines (the latter now merged into United Airlines) have stated that their airlines do not suffer from any noticeable drop in travel on those Fridays, according to the Stress Management Center.
Many people consider Friday the 13th to be similar to a night when there is a full moon.
Nurses often report more activity in the emergency room during a full moon. Police and other emergency responders often get more calls on these nights.
"There is no scientific data on it, but through stories from nurses and doctors you hear that more babies are born when there is a full moon or there is a higher utilization of the ER," said Francine Francis, spokeswoman for CHRISTUS St. Michael Health Center.
However, Francis said Friday the 13th does not appear to have the same kind of craziness associated with it.
"The director of out E.R. said they don't really see any more people than usual on Friday the 13th," she said.
Shawn Vaughn, a spokesman for the Texarkana, Texas, Police Department does not believe there is usually an increase in calls on Friday the 13th.
"Like everyone else, I think we tend to look at it with a bit of humor and go on with our normal business," Vaughn said.
It will not be visible here. But also today, a partial solar eclipse will be visible from the southeastern coast of Australia, Tasmania, and New Zealand's Stewart Island, as well as the northern coast of Antarctica, according to National Geographic. Earth has not seen a solar eclipse fall on a Friday the 13th since December 1974.