Three survivors spoke on Friday of the smell of burnt bodies and piles of the dead at Nazi Germany's Auschwitz death camp, one of whose former guards stands accused of helping in the murder of at least 170,000 people."If your ribs were visible, you were a candidate for the crematorium," said Leon Schwarzbaum, a 94-year-old survivor who lost 35 family members during the Holocaust.He was speaking at the trial of former guard Reinhold Hanning, also 94, who remained largely silent on the second day of his trial, showing no emotions as the survivors detailed their horrific experience.Hanning, sounding weak, was heard only once in court when asked how he was doing by judge Anke Grudda. "Fine," he responded.Dressed in the same brown tweed suit jacket as on Thursday, bespectacled Hanning - who was 20 in 1942 when he joined the camp as a guard - slowly walked into court where hearings are restricted to two hours given his age.Defense lawyer Johannes Salmen said a written statement would be read out on behalf of Hanning at a later stage of the trial. He added that it was possible that Hanning would also give a statement.Accused by the prosecutor's office in Dortmund as well as by 40 joint plaintiffs from Hungary, Israel, Canada, Britain, the United States and Germany, Hanning is said to have joined the SS forces voluntarily at the age of 18 in 1940. Although Henning wasn't directly involved in any killings at the camp, prosecutors accuse him of expediting, or at least facilitating, the slaughter in his capacity as a guard at the camp where 1.2 million people, most of them Jews, were killed.A precedent for such charges was set in 2011, when death camp guard Ivan Demjanjuk was convicted.Cross-examining the three witnesses, prosecutor Andreas Brendel tried to determine direct knowledge of the guard's duties in Auschwitz but none of them knew Hanning personally.In an earlier statement to the prosecution, Hanning has admitted to being a guard, but denied any involvement in the mass killings."We could see fire coming out the chimneys and it smelled of burned people unbearably," Schwarzbaum said when asked if it was possible that the guards were unaware of the murders.Erna de Vries, another witness, said she had to walk past piles of dead bodies each day on her way to forced labor in 1942, as the Nazis couldn't keep up with burning the bodies of people gased to death.Hanning's trial is the first of four Auschwitz lawsuits, which are likely to be Germany's last Nazi war crime trials.