National Geographic : 1942 Jul
Aussie Soldiers from the South Visit Darwin's Natural Wonders-Giant Magnetic Anthills The termite mounds rise like mammoth gravestones in fields a few miles from the town. Some are 12 feet tall. They arecalled magnetic because the thin edges invariably point north and south. During dry season, from April to the end of November, they are a dull gray.Inthewet season they turn almost black.