Greenland, and especially its northern regions of Ultima Thule, remains a land of fantastical and semi-mythical proportions, with aurora borealis, the vast tundra, glittering columns of ice, monstrous glaciers that calve icebergs into the sea and the proverbially tight-lipped Inuit. Ever since 15th-century explorers returned from the distant north with wild and woolly tales of a remote region of brutish hairy pygmies, unicorns, mind-bending visions and citadels of ice, Ultima Thule has been the fantasy of all fantasies. Poets from Virgil and Pytheas to Henry Wadsworth Longfellow have celebrated it in verse; the Weimar Republic used it as a template for one of their mythic Nordic-Germanic societies; and big-haired ''70s rock bands, with a penchant for heavy feedback and fuzzy guitar solos, have used it as a clarion call to youthful rebellion.