In the Earth Microbiome Project, an extensive global team co-led by researchers at University of California San Diego, Pacific Northwest National Laboratory, University of Chicago and Argonne National Laboratory collected more than 27,000 samples from numerous, diverse environments around the globe. They analyzed the unique collections of microbes—the microbiomes—living in each sample to generate the first reference database of bacteria colonizing the planet. Thanks to newly standardized protocols, original analytical methods and open data-sharing, the project will continue to grow and improve as new data are added.