It is often said that from tiny acorns great oaks grow.
More than 20,000 people will descend on Londonderry later as the largest Halloween party in Europe comes to a close.
Over the four-day Halloween festival's run, it is is estimated close to 80,000 will have visited Derry - a city named from the Gaelic word for oak grove.
So how did Northern Ireland's second city come to be among the world's premier Halloween destinations?
As with the greatest of oaks, Derry's Halloween celebrations have grown from humble beginnings.
Brian Doherty, then a city centre publican, is credited with being among those to start the celebrations.
He said in the mid 1980s, the Troubles impacted on every aspect of life.
"Derry was different place back then, it had a ring of security around the city walls and many people went to Donegal for entertainment.
"It was a bit of an effort to get people to come into the city centre when they were heading to Donegal," he told BBC News NI.
Mr Doherty owned Doherty's Bar in Magazine Street. With Halloween 1985 on the horizon, he made a decision do something different, unsure how his plans would transpire.
"Coming up to Halloween in 1985, I decided we would have a fancy dress party and encourage all the regulars to come in fancy dress.
"I was quite surprised to see a couple of dozen people in fancy dress. The entire place was mobbed by 8 or 9pm and there were 50 or 60 people in fancy dress. It was a bit of a surprise."
There were cavemen; more than one incredible Hulk, a few Ronald Reagans and even Margaret Thatcher put in an appearance.
A security alert would cut the night short, but spark some impromptu city centre festivities.
"We had a bomb scare and everyone spilled out along Castle Street and down Waterloo Street. Someone asked me last year if that was the first Halloween parade in Derry - I am not sure about that, but what I do know is that the following year everyone was doing fancy dress," Mr Doherty added.
He said from that point on it seemed that people realised it "was an opportunity to have a great time".
Official celebrations were quickly established on the civic calendar.
Johnny Murray worked as an events organiser with Derry City Council in the 1980s.
He said the first official celebrations as the decade drew to a close, were initially a little muted, but the festival's stock rose quickly.
"At the very first one, you might have had 10% of the people in fancy dress, the following year 40%, and the following year if you weren't dressed up you felt left out of it, so it literally took off from there," he said.
"We've never looked back since."
Spooky travel destination
In 2015, the city was named "best Halloween destination in the world" by a USA Today readers' poll.
Earlier this year, the New York Times named Derry as one of the world's six Spooky Travel Destinations for the Halloween Season.
On Tuesday night, the 31st year of official festivities, tens of thousands of people are expected to descend on Derry for the festival's closing Halloween parade and fireworks display over the River Foyle.
The parade begins at the council offices at Queens Quay at 19:00 GMT and is expected to last around 90 minutes.
Traffic disruption is expected in the city centre and the Peace Bridge will be closed from 19:15 until 20:40 GMT.
The parade route includes Boating Club Lane, Strand Road, Harbour Square Roundabout, the Foyle Embankment and Water Street.
Derry City and Strabane District council are urging people to avoid parking in the city centre and to allow extra time for their journey.
The closing parade and fireworks display will be streamed live on the BBC Radio Ulster and BBC Radio Foyle Facebook pages.