A series of historic archaeological findings were made in recent weeks at the Sobibor Nazi death camp in what was occupied Poland.

Archaeological excavations carried out at the site by Israeli and Polish researchers unearthed an escape tunnel, a crematorium, human skeletal remains, a substance that appears to be blood and the identification tag of a Jewish boy who was murdered in the camp. The findings shed new light on the camp, where around 250,000 Jews were killed between 1942 and 1943.

The excavations took place in an area called Camp III, where the gas chambers were located. Israeli archeologist Yoram Haimi, who works for the Israel Antiquities Authority, has been overseeing the excavations while working on his doctorate.

He told Haaretz on Friday, “The area we were excavating has been disturbed and plundered many times over the years since the war. It’s a mess containing human bones, human ash, glass, pieces of metal and a lot of waste.”

Haimi’s partner is Polish archaeologist Wojciech Mazurek. Their work is being supported by the International Institute for Holocaust Research at Yad Vashem, the Majdanek museum and the Foundation for Polish-German Reconciliation. The most important finding at Sobibor is the remains of the camp crematorium.

Read more at Haaretz.com.

This excerpt was amended on June 12 to reflect changes that Haaretz made in their piece.