Originally discovered by Bork the Bold, this cavernous island contains the Fireworm Queen and her highly flammable hive of Firecomb. The dragon riders successfully navigated their way here by following a lantern filled with Fireworms, which glowed brighter as they neared the nest.
— Hiccup's Map from Race to the Edge
This island may seem calm from above, but step inside one of it's many caves and you'll see that it's buzzing! Holding the cure for burnt-out dragons, the hanging firecombs make it look more like a beehive than a cave.
Three years after the end of First Berserker War, the Fireworm Queen's nest came under attack by a Cavern Crasher. She flew off to ask the Dragon Riders' help, particularly Snotlout, in chasing the intruder away, and they succeeded in doing so.