There’s an entire world of cells keeping the human body going — breaking down bits of food, defending us from invaders, and, sometimes, going wonky and wreaking havoc.

Now, a group of scientists is conducting a cellular census, surveying every tissue in the human body and finding out what cells actually live there. They’re part of the Human Cell Atlas (HCA) project, an international collaboration of almost 900 institutions in 62 countries.

“The goal of the Human Cell Atlas is to provide the reference map in order to understand and diagnose and treat human health and disease,” said Aviv Regev, co-chair of the HCA organizing committee and core member of the Broad Institute in Cambridge, Mass.

Members have already made some discoveries, including a new type of lung cellpublished by Regev and her colleagues in 2018, a finding that could lead to new cystic fibrosis treatments.

“I’ve always been fascinated by cells and in particular in understanding how cells actually work, what are the programs that make them go,” Regev said. “The atlas of cells will give us an unprecedented opportunity to recover those programs and understand how to make this remarkable thing called the cell actually work to our desires.”