I am not the same person I was last week. I think it would be impossible for anyone who has visited the Nazi concentration and extermination camps at Auschwitz to not be changed by the experience.

This year marks the 70th anniversary of the liberation of Auschwitz. The Nazis invaded Poland in 1939 and created the infamous camps on the occupied land.

I joined 200 school students from across the south west – including from Thomas Hardye School in Dorchester, Beaminster School, Sir John Colfox in Bridport, Woodroffe School in Lyme Regis and the Blandford School – for the one-day trip, organised by the Holocaust Educational Trust.

The HET works with schools and colleges on the Lessons from Auschwitz project. It aims to increase knowledge and understanding of the Holocaust based on the premise that ‘hearing is not like seeing’.

They could not be more right. No amount of reading of history books or watching of documentaries can prepare you for the sense of horror you feel walking through the infamous gates, with the sign Arbeit Macht Frei – ‘work makes you free’, knowing that you are walking in the footsteps of 1.1 million people who never made it out again – 200,000 of whom were children under 12.

Around 90 per cent of those killed at Auschwitz were Jewish. In total the Nazis killed six million of Europe’s 11 million pre-war Jews.

Other people sent to Auschwitz include Poles, Roma Gypsies, Soviet prisoners of war, Jehovah’s Witnesses, homosexuals, political prisoners and tens of thousands of people from other nationalities.

Of those who did not die in the gas chambers, many died of starvation, forced labour, diseases and executions.

What hit me most about the experience, and what these numbers cannot convey, is that every single one of those people was someone’s mother, father, grandfather, sister, uncle, cousin, friend or lover. Individuals just like you and me, who had a life, dreams and hopes for the future.

In Auschwitz 1 we saw rows and rows of 40,000 pictures of those brought to the camp, each dressed in the regimented striped pyjamas. Later, when photos were deemed too expensive, the Nazis tattooed prisoners with numbers.

We saw the punishment cells – spaces too small to stand up or lie down – where four or five people would be forced to spend the night.

We saw the piles of human hair, prosthetic limbs, spectacles, suitcases and shoes all taken from those arriving at the camps.

At Auschwitz-Birkenau we walked under the much-pictured guard tower and along the train tracks to the point of separation.

We stood on the spot where arriving groups were separated. Those deemed fit enough were sent to the labour camps and those deemed unfit – including the elderly, pregnant women and children – were sent to the gas chambers. What really got to me was the sheer size of Auschwitz-Birkenau – the rows and rows of stable blocks stretching into the distance.

There is a chilling feel to the entire place.

Standing next to the gas chambers our guide described how those including the elderly, women and children, were told to go in and take a shower.

The changing rooms are huge compared to the gas chamber itself, and we were told about the growing horror of the people who went in and the realisation of what was happening as more and more people were sent in – the mothers holding their children and comforting them, telling them it was going to be OK right up until the last moments.

I know I will remember the sense of shock and horror I felt walking around there for the rest of my life.

At the end of our visit there was a ceremony of remembrance and we all lit candles as a sign of hope and remembrance.

And standing there reflecting on everything I had seen and heard, I wish I was able to say I feel we have completely learnt the lessons of history.

But even now in 2015, people around the world are being discriminated against, persecuted and killed based on their beliefs, religion, gender, sexuality and race.

As I walked out though the gates, under the dark watch tower as the sun set, it hit me that I could leave. I could walk out from a place where 1.1 million died.

So what are the lessons from Auschwitz that I learnt? I am not the same person that walked in through those gates. I feel I have grown in a positive way.

The experience really made me think about the individual people, the faces, the lives, hopes and dreams of the people who were killed. They were not just six million – they were individuals.

What happened must never happen again and must never be forgotten and I feel a sense of responsibility to go out and tell people what I have seen.

It reaffirmed my feeling that we all have the responsibility to speak up for those who have no voice themselves and finally it made me realise there is always hope.