Amazing cross-section image of a termite mound (click to enlarge). Explanations are below.
Termites are among the most successful groups of insects on Earth, colonizing most landmasses except Antarctica. Their colonies range in size from a few hundred individuals to enormous societies with several million individuals. Termite queens have the longest lifespan of any insect in the world, with some queens reportedly living up to 30 to 50 years. Here is another cross-section image of a termite mound with some explanations:
Termite mounds in Namibia: