Students who visited Auschwitz this week said they could not put into words the shock they felt after learning about the events which happened at the camp.
From early 1942 until late 1944, transport trains delivered Jews to the camp's gas chambers from all over German-occupied Europe.
Around 1.3m people were reported to have died there - but some say the figure could be as high as 2.5m.
Leeds North East MP Fabian Hamilton took part in the trip to Auschwitz this week.
200 students from the Calendar region visited the camp - a trip organised by the Holocaust Educational Trust.
The MP recently found out his relatives were held in Auschwitz.
Andrew Percy, MP fro Brigg and Goole and Caroline Flint, MP for Don Valley, went with 200 students from across the Calendar region - many who are learning about the Holocaust - to Auschwitz this week.
It's one of the most horrific stories in human history. Of the six million people who were killed in World War two, more than a million were murdered in just one place - Auschwitz.
In order to show today's teenagers the extent of what happened there, the Holocaust Educational Trust took 200 students from schools across the Calendar region to Poland this week.