Up Helly Aa is the name of a spectacular Shetland Viking festival which always takes place on the last Tuesday of January.
The main celebration of Up Helly Aa takes place in Lerwick but there are 12 smaller local versions too all over the Shetland Isles.
The first official Up Helly Aa took place in Lerwick, Shetland's main town, in 1881.
Here's what you need to know:
Up Helly Aa (meaning Up Holy Day) is a huge spectacle, a celebration of Shetland history, and a demonstration of islanders' skills.
It harks back to Shetland's Viking heritage. As well as the main event there is a junior version, just for kids, which takes place on the same day.
The events last all day and involve a series of marches and visits, ending in a torch-lit procession and the burning of a Viking longship.
It's an event most of the local community takes part in, with loads of volunteers spending hours each winter getting ready for the big event and building the huge Viking longship that is at the centre of the festival.
Much of the preparations are done in strictest secrecy. The biggest secret of all is what the head of the festival, the Guizer Jarl, will wear and which character from the Norse Sagas - or stories from Norse history - he'll represent.
On the evening of Up Helly Aa almost 1,000 warriors or 'guizers', some in full Viking dress, parade in groups, known as 'squads', wearing helmets and carrying shields and swords.
Each guizer carries a fencing post, covered with sacking material soaked in paraffin.
In Lerwick, at 7.30pm, a firework explodes over the town hall.
The torches are lit, the band strikes up and the blazing procession begins, snaking through the streets with the Guizer Jarl standing proudly at the helm of his replica longship, or 'galley'.
It takes half an hour for the Jarl's squad of Vikings to drag him to the burning site, through a crowd of 5,000 spectators or more.
The Jarl leaves his ship, to a crescendo of cheers. A bugle call sounds, and then the torches are hurled into the galley.
As the blaze destroys the shipbuilders' work, the crowd sings the song The Norseman's Home.