Pupils from schools across south-west Hertfordshire took an emotional, often overwhelming journey this week, when they visited the Auschwitz-Birkenau concentration camp in Poland.

Sixth Form students from Parmiter's School, Bushey Hall, Francis Combe, Westfield, The Royal Masonic School and Rickmansworth School, joined others from across the East of England to tour the remains of the compounds on Tuesday.

The visit was organised by the Holocaust Educational Trust, as part of their Lessons from Auschwitz Project that ensures pupils from more than 1,000 schools in the country visit the camps every year.

Auschwitz was established by the Nazis in 1940 at some Polish army barracks near the city of Oswiecim, and was initially built to house the increasing number of Poles arrested after the German invasion of the country in 1939.

The camp, however, spawned into three separate areas, each with different purposes.

Arriving in Krakow after an early morning flight from Stansted airport, the 250-strong group first visited a cemetery in the small city of Oswiecim before travelling to Auschwitz I, a concentration camp that held between 15,000 and 20,000 prisoners.

Walking through the gates that read “Arbeit macht frei” (Work makes you free), the students toured the camp with a Polish guide and entered a number of barracks where they saw huge piles of possessions (such as toothbrushes and suitcases), clothes and shoes seized from prisoners as they entered the camps.

The mass of human hair, which had been shaved from both male and female inmates, had a particularly upsetting effect on some visitors.

The convey of coaches then travelled the short distance to Birkenau, which is also known as Auschwitz II and was the main death camp. Built in 1941, the massive site held 90,000 people in 1944 and was also the main extermination site that housed gas chambers and crematoria.

Students climbed the guard tower at the main entrance gates, before visiting some of the few remaining barracks where thousands of prisoners slept in cramped, cold and dirty conditions.

The remains of the gas chambers could also be seen, despite Nazi attempts to destroy them when they evacuated the site towards the end of 1944.

In total, up to 1.5million people, the majority of whom were Jewish, are believed to have died there between 1940 and 1945.

As darkness fell onto Auschwitz, the group gathered at the end of the railway track that brought prisoners into the camp, where Rabbi Barry Marcus from the Central Synagogue in London led a remembrance ceremony.

The group then walked the length of the railway to the front gates, placing candles beside the tracks.

Reflecting on their thoughts and feelings, many pupils said they had been surprised by the emotional intensity of the day.

Parmiter's pupil Avinoam Baruch, 17, said: “It was emotional being there, especially at Birkenau in the evening when it was very quiet, being where everyone went through that catastrophe. You could really feel it but during the day it was hard to take it all in. The main memory I will have is when it was becoming desolate in the evening, it was quite special to me.”

Alex Ellwood, 16, also from Parmiter's, said he didn't know what to expect from the trip.

“It was a bit surreal,” he said. “It's so dramatic and it's powerful when you go there. You are overwhelmed and you really feel it because you're not just being told the fact from a textbook. It was a brilliant experience.”

Bushey Hall students Sophie Frinton and Ben Forde, both 17, said they were “overwhelmed” by the size of the camps.

Sophie said: “The conditions they lived in were awful. The people who survived must have been really strong.”

Ben added: “It was eye-opening to see how cruel human beings can be. It was a good experience. I wouldn't have missed it for the world.”

Natasha Douglas, 17, from Francis Combe, said: “I don't think it's quite hit me yet. The first camp we saw felt worse because that was more visual and had more stuff to see.

“The hair was the thing that made me cry, just because of how much there was.

Her classmate TJ Watson, 17, agreed. “It was emotional to see all the hair and other things,” she said.

Pupils from Westfield, however, were able to draw parallels between Auschwitz and present-day events.

Jagmohan Singh Dhindsa, 19, said: “I don't think you can sum up the word for this. It's totally unique, something different. It was a very emotional trip.

“It was about reliving history because all these things are still happening now around the world, in Gaza and Zimbabwe. Things like when we went to Auschwitz 1, seeing little kids' shoes made me think of my nieces and nephews. That was when I got hit by it and it took me by surprise.

“From now on I'll value things a little more and show some more respect.”

Nousheen Imtiaz, 16, added: “It's been a great experience, an incredible journey. I cannot believe all of that has happened. We were standing on the grounds they were standing on.

“I think it's something unbelievable. It's just amazing I have seen it with my own eyes. I thought I was quite strong but afterwards you realise the effects. When I was looking at the children's clothes, I couldn't bear to look at it. It was hard.”