Step 1 : Introduction to the question "What iconic item is lit ablaze at the culmination of the Up Helly Aa festival in Scotland's Shetland Islands?"
The current Lerwick celebration grew out of the older yule tradition of tar barrelling which took place at Christmas and New Year as well as Up Helly Aa. Squads of young men would drag barrels of burning tar through town on sledges, making mischief. After the abolition of tar barrelling around 1874–1880, permission was eventually obtained for torch processions. The first yule torch procession took place in 1876. The first torch celebration on Up Helly Aa day took place in 1881. The following year the torchlit procession was significantly enhanced and institutionalised through a request by a Lerwick civic body to hold another Up Helly Aa torch procession for the visit of Alfred, Duke of Edinburgh. The first galley was introduced and burned in 1889. The honorary role of the 'Jarl' was introduced to the festival in the early twentieth century.
Step 2 : Answer to the question "What iconic item is lit ablaze at the culmination of the Up Helly Aa festival in Scotland's Shetland Islands?"
A traditional Viking longship:
On the final Tuesday in January every year, Scotland's Shetland Islands main port, Lerwick, is home to the Up Helly Aa fire festival. This largest of Europe's fire festivals celebrates the region's Viking heritage with traditional dance and music and a procession by torch-light that one must witness to appreciate fully. The culmination of the festival sees over 1,000 costumed "guizers" throw their burning torches into a "galley," the traditional Viking longship. Source: TravelAway.me