Few spoke during the harrowing visit and their bleak-faced expressions remained a constant as they took in the chilling sights, from the barracks, torture cells and gas chambers to the glass cases of human hair, shoes, prosthetic limbs, spectacles and luggage marked with the names of the dead.
Pupils were silent also as they trod in the footsteps of the one million men, women and children who were slaughtered, walking down the platform where families were unloaded and separated, across the tracks where an instantaneous decision was made about their fate and along the path to the gas chamber for those women, children and men who were not deemed suitable for the slave labour that awaited the others.
On the return trip to Glasgow, pupils spoke of how difficult it had been.
Kirsten Tingle, 17, from Douglas Academy, Milngavie, could not cope with the sight of baby clothes in a glass case. "I was doing OK, but just seeing that really makes you think that something like this really could have happened and that people let it happen and it brings the message home that you cannot let it happen again," she said.
"The things we were hearing were terrible ... I was trying to protect myself a bit, but seeing the baby clothes was so terrible and it makes you wonder how people could have done such a thing.
"We heard about how people were sending mothers and babies to the gas chambers and it didn't even cross my mind until coming here that was the case. It will stay with me for a long time."
Ryan McVey, 17, of St Andrew's Secondary School, Glasgow, was also deeply struck by the personal possessions left behind.
"What stood out most for me was the house keys, the women's make-up and the suitcases. Obviously these Jewish people thought they were going to somewhere other than a death camp and they had brought their possessions with them.
"I feel as if this is something people don't actually remember enough. I have been fortunate enough to have had this experience and I'm going to do what I can to make sure other people remember it too."