The witness has forced himself to testify. For the youth of today, for the children who will be born tomorrow. He does not want his past to become their future.

--Night, by Eli Wiesel.

This week, just after the death of Eli Wiesel, I traveled with my family to Auschwitz, the largest crime scene in world history.

Nowadays it’s a gruesome but essential tourist destination in Oswiecim, Poland, an hour and a half west of charming Krakow. A visit to Auschwitz (the German name for the area) includes a devastating three-hour guided tour, the only way summer visitors are allowed in the camps.

Wiesel’s classic book Night, which went from selling 1,000 copies when first published in the indifferent 1950s to more than 10 million today, offers a shattering supplement to the experience.

Last week’s Wiesel obituaries were all fine, but they couldn’t fully bear witness to his ordeal. The important thing for this most honored of survivors wasn’t remembering him as much as remembering his Holocaust experience—and the lives and deaths of the millions who weren’t lucky enough to tell their own stories.

Any one of the fields of ashes in Birkenau carries more weight than all the testimonies about Birkenau.

Wiesel was being modest about his own historic testimony, which will no doubt still be read a century from now. But he was right about seeing those ash pits—where small flecks of human bone are still visible in a swampy hole.

The remnants the Poles have preserved at Auschwitz are less artfully mournful than the Holocaust Museums of Berlin and Washington--and less sacred than Israel’s Yad Vashem--but they deliver emotional body blows impossible to replicate beyond the fences of concentration camps.

While the site features the usual snack shops and even some unwelcome graffiti in a cellblock reserved for non-Jewish children (the Jewish children there were all annihilated), the experience is tasteful, and it generally silences even the noisiest of tourists.

In our tour group of 30, led by a bright and emotional Polish mother raised nearby, few took pictures and none—including us—asked questions. Even the most substantive ones would have felt trivial amid the Zyklon B canisters and mounds of hair, shoes and eyeglasses taken from Jews and piled in the rough-hewn museum housed in one of the barracks.

Our guide started by explaining that Auschwitz, where more than 1.1 million Jews—plus two hundred thousand Poles, gypsies, homosexuals and others—died between 1940 and 1945, is actually three large sites, now known as: Auschwitz I, the original camp commandeered from the Polish Army by the Nazis, where the mocking ARBEIT MACHT FREI (“Work makes you free”) sign greeted Polish inmates who were quickly worked to death; Auschwitz II, better known as Birkenau, the sprawling extermination camp built from scratch by inmates three kilometers away and named for the surrounding birch trees, where once stood scores of wooden barracks, four gas chambers and four crematoria; and Auschwitz III, also known as Monowitz-Buna, an I.G Farben rubber plant that employed slave labor and where another factory sits today.

Wiesel spent time in all three at various times in 1944 and 1945, with Auschwitz-Birkenau the first and worst.

“There are eighty of you in the car,” the German officer said. “If anyone goes missing, you will all be shot like dogs.”

As late as the spring of 1944, the Wiesel family of Sighet, Hungary (the country with the most Auschwitz victims) thought it was safe from the distant war. But in a matter of weeks, their lives were upended. A fascist party preaching hate and exclusion took power in Hungary; the once-friendly Hungarian police—collaborating like so many when faced with a strong hand—placed the Jews in ghettos, with many Jews still rationalizing the change as not so bad; and Wiesel’s father, a highly cultured store-owner, rejected an offer from their Christian housekeeper to hide them in the countryside. Then they were told to reduce all of their worldly possessions to 25 kilograms (about what’s allowed today in airline carry-on) and crammed into a sealed cattle car with a bucket for waste, destination unknown.

Within moments of arrival, Elie, a 15-year-old Torah student, was quickly advised by an inmate to say he was 18. His 50-year-old father was told to say he was 40. This helped make them the right ages to be slave laborers.

“Men to the left! Women to the right!” I walked on with my father, with the men. I didn’t know that this was the moment in time and the place where I was leaving my mother and Tzipora [his seven-year-old sister] forever.

The” selection area” by the railroad siding, depicted in many movies, seems ordinary enough in the summer sun. This is where Dr. Josef Mengele decided whether to send the new arrivals to be registered as inmates or—if too old or young for back-breaking work—right to the gas chambers.

Wiesel, who told Mengele he was a farmer (the best answer because it helped him avoid rough construction duty), was pointed left. His odds of survival remained terrible. Those who couldn’t somehow find extra rations lasted just a few months. Seven decades ago, the fields we see contained little grass because inmates ate it.

Something was being burned there. A truck drew close and unloaded its hold: Small children. Babies! Yes, I did see this, with my own eyes…children thrown into the flames.

Our group began walking right, about a half mile down a road lined with ditches. We imagined seeing smoke pouring out of the crematoria as the kapos—the inmates in charge of other inmates—beat us into line, hoping a little cruelty would curry favor with the Nazis. After a few Germans died of typhus during a 1942 outbreak, they generally used kapos to touch or strike inmates, though shooting them remained a task for Nazis.

But shooting was very inefficient. At Auschwitz, the machinery of death required an assembly line. The condemned, just off the train, were sent into “undressing rooms” and told to strip for a shower. The gas chambers were designed by Nazi architects to be below ground and half the size of the undressing rooms in order to hold the heat—the body heat—necessary to activate the Zyklon B.

We learned that 700-2000 people could be crammed into a gas chamber at one time and all would be dead within 20 minutes.

The gas chambers were blown up by fleeing Nazis and the ovens—so inadequate to the task of incinerating thousands of bodies a day—are twisted ruins now. For greater efficiency, most of the bodies were eventually burned in large open pits. Today, on ground still full of human ashes, one pit has become a little memorial.

The barrack we had been assigned to was very long. I thought: This is what the antechamber of hell must look like. So many crazed men, so much shouting, so much brutality.

The prisoners had to sleep sideways on wooden slats with no bedding. Eight prisoners crammed together in the favored top compartment. Six in the middle. Five in the desperate bottom, sleeping on the freezing ground, fighting off rats and almost certain death.

That evening, in the latrines, the dentist pulled my [gold] crown with the help of a rusty spoon.

We learned that inmates got a shower—freezing in the winter and boiling in the summer, for maximum psychic torture—once a month at best. In the latrine, they had 20 seconds to defecate and no toilet paper. Our guide reminded us of the scene in Schindler’s List where a boy in another concentration camp in Nazi-occupied Poland hides in the hole. Not here. The Nazis put in screens to prevent it.

What had happened to me? My father had just been struck, in front of me, and I had not even blinked. I had watched and kept silent.

As the Soviets advanced, the Germans transported Wiesel and other inmates to Buchenwald at the end of the war, where he watched his father die beside him shortly before liberation. Wiesel's two older sisters also survived and he was reunited with them after the war.

Drained after the long tour, we took the bus back to Krakow. I read the appendix to the new edition of Night. It’s Wiesel’s 1986 Nobel Peace Prize acceptance speech, which he devoted to the plight of suffering people everywhere.

“What all of these victims need above all is to know that they are not alone; that we are not forgetting them, that when their voices are stifled, we shall lend them ours; that while their freedom depends on ours, the quality of our freedom depends on theirs.”