Traces of an escape tunnel have been uncovered at the site of an infamous Nazi death camp in Poland, according to news reports. 
 
 Archaeologists say the passageway, found 5 feet (1.5 meters) below the surface, spanned 32 feet (10 m) and reached beyond the barbed-wire border surrounding the extermination camp at Sobibor, The Telegraph reported. 
 
 "We were excavating near where the sonderkommando barrack was and we came across two rows of buried barbed wire," Polish archaeologist Wojciech Mazurek was quoted as saying by The Telegraph. "Digging down we found the traces of the tunnel. It was about as wide as a human, and we are 99 percent certain that it was an escape tunnel." [8 Grisly Archaeological Discoveries] 
 
 Sobibor was operated in German-occupied eastern Poland between 1942 and 1943. Estimates for the number of people killed there range from 167,000 to upwards of 250,000. Virtually all of the victims were Jews and most were gassed upon arrival. Some prisoners were spared immediate death and kept in the work units known as the sonderkommando, forced to help in the gas chamber operations and the disposal of bodies. 
 
 The researchers digging at the site reportedly don't have any evidence that the newly discovered escape tunnel was ever actually used. Prisoners at Sobibor did, however, stage an uprising in October 1943. Six-hundred prisoners revolted and managed to kill nearly a dozen of their guards. Many of the 300 laborers who broke out of the extermination camp were eventually captured and killed, and only 50 escapees are believed to have survived the war. 
 
 After the uprising, Nazi officials leveled the camp and covered its traces. That makes work difficult for archaeologists trying to understand the site. 
 
 "The area we were excavating has been disturbed and plundered many times over the years since the war," Yoram Haimi, an Israeli archaeologist who is also investigating the camp, was quoted as saying by Haaretz. "It's a mess containing human bones, human ash, glass, pieces of metal and a lot of waste." 
 
 Excavations have been underway at Sobibor for more than a decade. In addition to the escape tunnel, the team has reportedly found a crematorium, human skeletal remains, and dozens of artifacts including eye glasses, jewelry and sobering personal items, like a Mickey Mouse pin, that seem to have belonged to children. 
 
 Follow Megan Gannon on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on LiveScience.com. ||||| Lying five feet below the surface, the tunnel stretched for 32 feet from one of the barracks and under the barbwire fences surrounding the camp. 
 
 Its discovery provides the first physical evidence of prisoners trying to dig their way out of a Nazi death camp. 
 
 The length of the tunnel gives an indication of the ingenuity of prisoners desperate to escape a camp that claimed the lives of an estimated 250,000 in the 17 months of its operations in German-occupied Poland . 
 
 "We were excavating near where the sonderkommando barrack was and we came across two rows of buried barbed wire," said Wojciech Mazurek, from the archaeological team. "Digging down we found the traces of the tunnel. 
 
 "It was about as wide as a human, and we are 99 per cent certain that it was an escape tunnel." 
 
 The sonderkommando was comprised of prisoners tasked with herding victims to the gas chambers and disposing of the bodies. Their function at Sobibor would have spared them the death on arrival that awaited so many of the camp's victims, and given them the time to excavate the tunnel. 
 
 The tunnel's discoverers believe it is unlikely that anybody ever used it to escape the camp. There were no reports of successful escape attempts from Sobibor until 600 prisoners broke out during an armed uprising in October 1943. 
 
 Experts said that the tunnel was probably discovered, and everybody who might have been connected with it executed. The excavation was apparently then filled in. 
 
 Its discovery has shed new light on the history of a camp of which little is known in comparison to other German extermination sites. 
 
 Few people survived Sobibor. Not long after the uprising, Himmler ordered the camp to be razed to the ground and trees planted in an attempt to erase all traces of the facility. ||||| The first-ever archaeological excavations at the Nazi death camp Treblinka have revealed new mass graves, as well as the first physical evidence that this camp held gas chambers, where thousands of Jews died. 
 
 Presented in a new documentary, "Treblinka: Hitler's Killing Machine," which will air Saturday (March 29) on the Smithsonian Channel, the excavations reveal that the Nazis weren't as adept at covering up their crimes as they believed when they razed the death camp in 1943. Brick walls and foundations from the gas chambers remain, as do massive amounts of human bone, including fragments now eroding out on the forested ground surface. 
 
 "For me, that was quite shocking," said project leader Caroline Sturdy Colls, a forensic archaeologist who normally works with police to find modern murder victims. "These artifacts are there, and these human remains are on the surface, and they're not being recorded or recovered." 
 
 Treblinka's horror 
 
 Of all the atrocities of Hitler's Third Reich, Treblinka is one of the most mind-boggling. Historians estimate that about 900,000 Jews were murdered at this concentration camp in Nazi-occupied Poland over a mere 16 months. 
 
 The Nazis began deporting Jews, mostly from the ghettos of Warsaw and Radom, to Treblinka in July 1942. 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, a horrendously efficient death camp. [7 Absolutely Evil Medical Experiments] 
 
 Jews were sent to Treblinka II on trains, told they were simply 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," Colls told Live Science. "It was run by a famous composer at the time, Artur Gold." 
 
 Gold, a Jewish violinist from Warsaw, was kept alive at Treblinka both to entertain the Nazi guards and to run the orchestra. He died at the camp in 1943. 
 
 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 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. 
 
 Hidden atrocities 
 
 But because the Nazis razed Treblinka's death camp in 1943, little physical evidence of this genocide remained. What was known about Treblinka came from Nazi confessions and the eyewitness descriptions of very few survivors, most of whom were never allowed near the gas chambers. [Images: Missing Nazi Diary Resurfaces] 
 
 But as an archaeologist, Colls knew that "the landscape could never be sanitized in that way," she said. She began assessing Treblinka as an archaeological site in 2007. Her emphasis was on using "non-invasive" archaeological methods, including geophysical surveys of the site and visual inspection. 
 
 "What we wanted to do at that stage was to asses what, if anything, survived below ground," Colls said. 
 
 Since that time, Colls has also led a lidar survey of the wooded site. Lidar is a method that uses lasers to measure the distance between the ground and the airplane-borne instrument. By scanning the ground with lidar, archaeologists can detect depressions and mounds that might indicate manmade structures. Lidar allows researchers to virtually strip away the vegetation that might obscure these features on the ground. 
 
 "What that revealed was the presence of previously unknown mass graves," Colls said. 
 
 The suspected mass grave sites were in Treblinka I, the labor camp. The story of the labor camp is less well-known than the story of the death camp, which is now marked by a memorial. But the labor camp was no less brutal, Colls said: Eyewitnesses report seeing men hacked to death alive, and beatings and murder were commonplace. The largest of the mass graves as revealed on lidar was 63 feet by 58 feet in size (19.2 by 17.6 meters). 
 
 Indeed, when the archaeology team began digging to confirm the lidar results, they uncovered shoes, ammunition, and bones — including bones with cut marks indicating that the victims had been stabbed or otherwise assaulted. 
 
 After digging three small test trenches to confirm each mass grave, Colls and her team reburied the remains. Jewish rabbinical law prohibits the disruption of a gravesite, so the aim was never to disinter the bodies. But placing the bones back in the grave was emotionally difficult, Colls said. 
 
 "I think it never actually crossed my mind that it would actually be me who would re-inter the remains," she said. "I think sometimes the hardest thing to do was to actually re-inter the remains, and to backfill the trenches over the gas chamber, for example, because it felt like you were almost putting a lid on it." 
 
 Finding the gas chamber 
 
 The gas chamber was the subject of the teams' second dig. 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. 
 
 Colls and her team conducted four excavations at Treblinka II. The first two revealed a strange find — a fossilized shark tooth, and sand. Evidently, the Nazis dumped sand from a nearby quarry over the remains of the death camp to disguise them. 
 
 The second two trenches, however, revealed a brick wall and foundation. The gas chambers were the only brick buildings in the camp, Colls said. The excavations also revealed orange tiles that matched eyewitness descriptions of the floor of the killing chambers. Chillingly, each tile was stamped with a Star of David, likely part of the Nazi subterfuge that the building was a Jewish-style bathhouse. 
 
 "Treblinka had never been looked at since the period after the war," Colls said. "And everybody had assumed that because the history books said it was destroyed, it was." 
 
 The excavations prove otherwise, she said. Colls is now working on an exhibition of the findings to go on display at Treblinka, as well as a book about the work. There are plans to go back and dig at an execution site near the labor camp to confirm the presence of a mass grave, she said, and there may be more work near the gas chambers. 
 
 The hope, Colls said, is to bring the atrocities to light, understand them, and hopefully prevent future genocides. To that end, she says, she channels the emotion of uncovering victims' remains to finding more answers. 
 
 "For me, it feels like the Holocaust happened yesterday," she said. 
 
 "Treblinka: Hitler's Killing Machine" premiers Saturday, March 29 at 8pm ET/PT on the Smithsonian Channel. 
 
 Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.
– Archaeologists think they've found the first evidence of prisoners trying to dig their way out of a Nazi death camp. The find comes after more than a decade of excavations at the Sobibor camp in Poland; Nazis leveled the place after its prisoners revolted in 1943, LiveScience explains. In the course of their work, the team last month "came across two rows of barbed wire," one archaeologist tells the Telegraph. "Digging down we found the traces of the tunnel. It was about as wide as a human, and we were 99% certain that it was an escape tunnel." The tunnel, found 5 feet below ground, runs an astonishing 32 feet, from under where one of the barracks once stood to the other side of the barbed wire. The Telegraph explains that the barracks in question would have housed the sonderkommando: prisoners tasked with bringing victims to—and bodies out of—the gas chambers. Having avoided an immediate death, archaeologists speculate they would have had time to work on the tunnel. There's no evidence of whether it was actually used.