“Invisible microbes have created some of the largest structures on the planet. Mycorrhizal fungi form extraordinary subterranean networks that associate symbiotically with plant roots. Most land plants, including many human crops, need mycorrhizae for optimal growth, but recent research has shown they also play important roles in forest-wide communication and may even turn some trees into carnivores. More dramatically, microbial communities have created global landmarks ranging from the White Cliffs of Dover to the Great Barrier reef.”