More than one million people were killed at Auschwitz in Poland during the Holocaust.
The majority were Jews and people that did not fit into the Nazis' view of the perfect world.
The majority of the concentration camps set up by the Nazis in World War Two were destroyed when the Holocaust was liberated, but Auschwitz-Birkenau was kept as a museum.
Survivors lay wreathes and lit candles to mark 70 years since the camp's liberation, and to remember those who never left.
WATCH: THE BBC FLEW A DRONE OVER AUSCHWITZ AND THE FOOTAGE WAS HAUNTING