Up-Helly-Aa is a Norse festival on Shetland during which a replica Viking longship is burned. It is to celebrate the 24th day after Christmas, or Up Helly Night. The festival is relatively new in Lerwick (early 19th Century) and has evolved over time. In 1840 a tar barrel raft was burned as part of the proceedings. By the 1870’s the long ship and Norse costumes were introduced.