Last week, the Cowessess First Nation in Saskatchewan found 751 unmarked graves at the site of a former residential school, just one month after more than 200 unmarked graves were found at another school in British Columbia.For generations, indigenous children in the United States and Canada were forcibly sent to boarding schools to assimilate. Exactly what happened at those schools is still being uncovered.What do we know about what happened at these schools? And what will this investigation mean for the indigenous communities directly impacted?Want to support 1A? Give to your local public radio station and subscribe to this podcast. Have questions? Find us on Twitter @1A.