A heartbreaking find of 751 unmarked graves have been discovered at site of a former residential school in the prairie province of Saskatchewan, Canada.

According to the Washington Post, this is the second such discovery in less than a month. Recently, a horrific discovery of the remains of 215 Indigenous children was made on the grounds of a former residential school in Kamloops, British Columbia.

According to a statement released Wednesday by the Federation of Sovereign Indigenous Nations, which represents 74 First Nations in Saskatchewan, the Cowessess First Nation made the “horrific and shocking discovery” at the site of the former Marieval Indian Residential School in the southeastern part of the province.

The outlet reports that nearly 150,000 Indigenous children were sent to the government-funded and church-run boarding schools, which were set up in the 19th century to assimilate them and operated until the late 1990s. Many children were forcibly separated from their families to be placed in the schools.

In a 2015 report, Canada’s Truth and Reconciliation Commission said that many of the students were subjected to physical and sexual abuse at the schools. The schools also barred them from practicing their traditions and speaking their languages.

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