The Human Epigenome Project is a research effort to figure out how certain genes are turned on or off in people's bodies. It’s like a map that helps us understand how cells know when and how genes should be expressed. Genes are what give us different characteristics, like blue eyes or brown hair, so understanding how they turn on and off helps us learn more about our bodies and how they react to different things. The project is international and involves many different countries, each contributing data and information to help create a more complete picture of the human epigenome.