These are Magnetic Termite Mounds. The remarkable thing about these mounds is that they line up (more or less) with magnetic north. The thin axis of the mound points North/ South, which means the flat sides face east and west.
It is thought that this helps with the temperature regulation of the mounds - in the hottest part of the day, when the sun is to the North or South of the mounds, only a thin section is presented to the sun. In the cooler parts of the day - dawn and dusk - the mounds collect sunlight on a wide face. Simple, but elegant.
These mounds are at a well know location in the Litchfield National Park in the Northern Territory.
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