America’s once-abundant tallgrass prairies—which have all but disappeared—were home to dozens of species of grasses that could grow to the height of a man, hundreds of species of flowers, and herds of roaming bison. For the first time, a research team led by the University of Colorado Boulder has gotten a peek at another vitally important but rarely considered community that also once called the tallgrass prairie home: the diverse assortment of microbes that thrived in the dark, rich soils beneath the grass.