During this combustible holiday, costumed men carry nearly 1,000 torches through Lerwick, Scotland, in a procession that ends with the burning of a Viking-style ship.

On the last Tuesday of every January, the capital city of Lerwick, on the Scottish main island of Shetland, goes up in flames.

During a celebration known as Up Helly Aa, costumed men carry nearly 1,000 enormous torches through the Scottish city’s streets in a procession that ends with the burning of a Viking-style ship.

The festival evolved from early 1800s Christmas Eve and New Year’s celebrations, when local men would set tar barrels on fire and carry them through the streets. The celebration was formalized in 1870, when “tar barrelling” was outlawed, and disguises and torches became the standard participant trappings.

The Viking-style galley ship was not introduced until the 1880s, but heralding Shetland’s Scandinavian roots has become a key piece of the festivities. The Shetland Islands were given from Norway to Scotland in the 15th Century as part of a royal dowry. Playing on Norse tradition, the Up Helly Aa committee annually selects a Guizer Jarl (the Norse word for “earl”), who leads the honoured Jarl Squad, whose members dress in full Viking attire during the procession.

About 45 other squads make up the rest of the torch-bearers and most take more liberties with their costumes. From ballerina tutus to schoolgirl skirts, the common cross-dressing choices have earned Up Helly Aa the nickname “Transvestite Tuesday”.  Only men who have been residents of Shetland for at least five years are eligible to belong to a squad and walk the procession, but all visitors are welcome to watch and take part in the evening’s revelry.

After singing The Norseman’s Home”, the traditional anthem of the festival praising Norse heroes,   and throwing their torches on the galley, the squads retreat to local halls to perform prepared acts and dances. With festivities lasting well into the morning, Lerwick always recognizes the following day as a public holiday, giving residents time to recover and start preparing for next year.