In the oxygen-free microenvironment of an insect's gut, come face-to-face with hundreds of species that exist nowhere else on the planet. These microbes enable their termite host to digest the wood it infamously devours. The termite and the microbes share what is called an "obligate endo-symbiotic" relationship. That means that they help each other, that neither could survive without the other's help, and that one species lives inside the other. A lot of people dislike termites, so it should be noted that only ten percent of the 2500 species of termite on Earth cause damage to human habitation. In fact, termites are absolutely essential to recycling dead plant material. Without them, and these invisible microbes too, the surface of the Earth would be buried under miles of rotting plant material piled up over millennia. The microbes are shown here magnified between 100-400 times actual size using darkfield microscopy. This program was produced with the generous assistance of Jared Leadbetter, Professor of Environmental Microbiology at the California Institute of Technology.