Naturally occurring structures include canyons such as the Grand Canyon in the United States, mountains such as Mount Everest, and even homes and nests that animals make for themselves, including beehives, ant hills, bird nests and beaver dams. Any form that stands on its own and has a definitive form that was not made by man is considered a natural structure. This is in contrast to man-made structures like buildings and bridges.
Beehives are fantastic examples of the potential complexity and smart design of natural structures. Using materials readily available in nature and following an adapted pattern of behavior that is known by other bees, these insects build complex hives with hexagonal chambers in which to store honey, wax and young bees.