Thousands of people have flocked to Londonderry for the 2016 “Out of this World” Halloween festival.
A number of road closures are in place throughout the city centre, but who needs transport infrastructure when you’re a ghost or a ghoul?
Even a slight drizzle earlier in the evening did nothing to dampen spirits.
The parade in the renamed City of Bones began at 19:00 GMT, followed by fireworks from 20:00 GMT.
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Londonderry now lays claim to being the “best Halloween destination in the world” having been voted number one in a USA Today readers’ poll last year.
The festival, organised by Derry City and Strabane District Council, is now in its 30th year.
One of the organisers told the BBC an estimated 30,000 people had gathered in the city for the culmination of the four-day festival, which had already attracted an estimated 40,000 people over the weekend.
Ch Insp Gordon McCalmont, who is in charge of the policing operation, said about 200 officers were involved.
He said the operation was “not without its challenges” but it was also “thoroughly enjoyable”.
At the spooky scene
By BBC NI’s Niall Glynn
Londonderry’s Halloween celebrations may have started small with a fireworks display 30 years ago, but they have grown into a four-day festival attracting tens of thousands.
It’s first and foremost a family affair, with hundreds of children on parade and hundreds more lining the streets to watch, most of them decked out in fancy dress.
But it’s not just the kids who dress up, the adults get into the spirit of it too with Star Wars characters, creepy clowns, ghost busters and some frankly indecipherable homemade costumes on display.
The parade itself featured everything from Celtic mythology and spooky dancers to environmental messages and even a likeness of Donald Trump.
The event reached a climax with a stunning fireworks display over the river Foyle.
An invitation was extended to extra-terrestrial guests, and a World War Two siren wailed across the city to “prepare earth residents for their arrival”.
After the parade ended at Queen’s Quay, the fireworks provided a spectacular finale for the entire Derry and Strabane area, with the council spending 30,000 on the display.
“The world knows no-one throws a Halloween party like us,” said Mayor of Derry City and Strabane District Council Hilary McClintock.
“For 30 years now, people from all over the world have visited our city and celebrated with us in our unique Halloween celebrations, making memories and great friends during their visit.”
Jacqueline Whoriskey, from Derry City Council, told the BBC it cost about 220,000 to put on the Halloween celebrations across the district.
It was not just all about 31 October – the city has been partying hard for the last three days.
Derry’s Halloween festival officially began on Friday, with a packed weekend programme of “freaky family fun”.
There was live music, street performances, ghost tours, spooky story-telling, fancy dress dances, a food and craft market and a 5km “zombie run”, with the city’s historic 17th Century walls a dramatic backdrop to the four days of festivities.
It was all a far cry from the festival’s humble beginnings 30 years ago.
Earlier this month, council worker Seamus Carlin shared his memories of Derry’s first Halloween carnival in 1986.
“It started as a small event in the Guildhall Square with some fireworks,” recalled the building maintenance foreman.
“It took us six hours to build the ‘shamrock stage’ on the first year of the event.”