Few sites across war-torn Poland harbor more secrets of atrocity and horror than the Nazi concentration camp of Sobibor. Different from Auschwitz, which almost immediately yielded the full scope of the crimes committed there, the history of Sobibor in eastern Poland was initially hidden and opaque.

Unlike Auschwitz, the fate of Sobibor wasn’t liberation. It was obliteration. The Nazis who had run the camp tried to extinguish every remnant of it in 1943, painting over its grounds with a farm, trees and asphalt. Besides a railroad track and the commander’s house, Haaretz noted, nothing remained of the camp. Save for the testimonies of the few survivors, who could only provide scant recollections of small areas of the camp, Sobibor had been lost to history.

But now, more than 70 years later, relics of genocide have surfaced, bringing more clarity to the murder of an estimated 250,000 Jews there than ever before. Buried beneath an asphalt road were a series of well-preserved gas chamber walls that archaeologists say will help elucidate the secrets of Sobibor. Beneath the road were brick rows, stacked four deep — the exoskeleton of four gas chambers.

“The discovery of the gas chambers at Sobibor is a very important finding in Holocaust research,” historian David Silberklang, editor of Yad Vashem Studies, said in a statement. “It is important to understand that there were no survivors from among the Jews who worked in the area of the gas chambers. Therefore, these findings are all that is left of those murdered there, and they open a window onto the day-to-day suffering of these people.”

But the discoveries didn’t end with the gas chambers. Thousands of items that belonged to those murdered were also left buried in a well the Germans had plugged. “We found earrings, gold wedding rings and a ring with the inscription, ‘with this ring you are consecrated to me,’ in Hebrew letters,” Israeli archaeologist Yoram Haimi told Haaretz. “We also found a large Magen David [the Star of David] and a coin dated 1927 from Palestine.”

Taken together, the mementos retell the story of Sobibor — a story as much of resistance as it was of the Holocaust. Established in March 1942, the camp was cramped and small, extending 1,300 by 2,000 feet, according to the Jewish Virtual Library. It was composed of three parts: administration, barracks and gas chambers — brick buildings into which carbon monoxide was fed. Before the chambers was a road called Himmelfahrsstrasse: “Road to Heaven.”

When Jews arrived at those buildings, a man stood dressed in a white coat, according to one German officer who later testified to what happened there. “He used to wear a white coat to give the impression he was a physician,” the officer said, according to the Holocaust Education and Archive Research Team. He “announced to the Jews that they would be sent to work. But before this they would have to take baths and undergo disinfection. … After the Jews had entered the gas chambers, the Ukrainians closed the doors, the motor was switched on … and after the gassing, the doors were opened and the corpses were removed.”

Polish archaeologist Wojciech Mazurek said Nazis bred geese at the site. It was “to drown out these shouts so that prisoners could not have heard these shouts, these torments,” Reuters quoted him saying.

But then the flow of prisoners entering the camp began to winnow, and its inhabitants began to suspect they all would soon be killed, according to Sobibor Interviews.

This was also around the time a man named Alexander Pechersky, a Jewish Soviet prisoner of war, arrived at the camp. He soon devised a plan that would twin vengeance with escape: Kill as many Nazi guards as possible and then bolt free.

The uprising surged on Oct. 14, 1943, and several guards were killed, sending hundreds of prisoners fleeing into the surrounding woods. Many were tracked down and killed, but some were not — and their triumph led to the camp’s closing.

As the Germans pulled out, they tried to wipe clean any sign of what occurred there — the lives lost, the items prisoners had kept. For years, “the site has remained bare, lacking any characteristic traces of it being a former extermination camp,” according to Yad Vashem.

Only now, researchers said, are the gaps in the narrative filling in. “After eight years of excavations at Sobibor, this is a great achievement,” said researcher Yoram Haimi, who lost two uncles at the camp. “We have reached our goal — the discovery of the gas chambers.”