Holocaust prisoner
Holocaust prisonerThinkstock

The first-ever archaeological excavations at the Nazi death camp Treblinka in Poland have revealed new mass graves, as well as the first physical evidence that this camp held gas chambers. The camp had been bulldozed in 1943. To cover their tracks, the Nazis went so far as to plant crops and build a farmhouse on the leveled ground.

Presented in a new documentary, "Treblinka: Hitler's Killing Machine," which aired Saturday on the Smithsonian Channel, the excavations revealed brick walls and foundations from the gas chambers, as well as mass graves and massive amounts of human bone, some of which was close to the ground's surface or exposed to the elements.

Historians estimate that about 900,000 Jews were murdered at the camp over just 16 months.

The Nazis began deporting Jews to Treblinka in July 1942, mostly from the ghettos of Warsaw and Radom. There were two camps: Treblinka I was a forced-labor camp where prisoners were made to manufacture gravel for the Nazi war effort. A little more than a mile (2 kilometers) away was Treblinka II, the death camp, where Jews were sent on trains.

The victims were told that they were going to a transit camp before being sent on to a new life in eastern Europe. The deception was elaborate: Nazis erected a fake train station in the remote spot, complete with false ticket-counter and clock.

"There was an orchestra set up near the reception area of the camp to play," archaeologist Caroline Sturdy Colls told Live Science. "It was run by a famous composer at the time, Artur Gold." 

The gas chamber was the subject of the teams' second dig. The excavations revealed a brick wall and foundation. There were two sets of gas chambers built at Treblinka, the first with a capacity of about 600 people, the second able to hold about 5,000. The gas chambers were the only brick buildings in the camp, Colls said. The digs also revealed orange tiles that matched eyewitness descriptions of the floor of the gas chambers. Each tile was stamped with a Star of David, apparently in order to fool the victims into believing that the building was “a Jewish-style bathhouse.”

The Jewish deportees were split into two groups, one of men and the other of women and children, and ordered to undress for "delousing." After handing over their valuables and documents, the victims were sent to the gas chambers, which were pumped full of exhaust fumes from tank engines. “Within about 20 minutes, some 5,000 people inside would be killed by carbon monoxide poisoning. Corpses were initially buried in mass graves, but later in 1942 and 1943, Jewish slave laborers were forced to reopen the graves and cremate the bodies on enormous pyres,” adds Live Science.

After the war, Treblinka was turned into a memorial. Out of respect for the victims, no excavation was allowed there, until Colls and her colleagues won approval from Polish authorities as well as Jewish religious leaders to conduct a limited dig.