Monday 27 January 2020 will mark 75 years since the Nazi extermination camp Auschwitz-Birkenau was liberated by the Soviet Army. Today, the camp is a symbol of the tragedy of the Holocaust.
While other Nazi concentration camps sewed prisoner identification numbers on clothes, Auschwitz guards marked prisoners with permanent tattoos.
Survivors of the camp, many now in their 90s, still carry this lifelong reminder of inhumanity with them.
Agi Geva, pictured below, told an audience at the US Holocaust Memorial Museum that she promised her mother she would never remove the tattoo surgically because it was "living proof" of having survived the death camp.
The first prisoners tattooed at Auschwitz were Soviet prisoners brought to the camp starting in 1941, according to the US Holocaust Memorial Museum. Most of these Soviet prisoners died.
Jewish prisoners were tattooed at the camp starting in 1942. The identification number was tattooed on the left forearm, usually on the outside, though sometimes it was done inside the forearm.
In February 1943, as indicated by a file written by the commandant of Auschwitz, the systematic tattooing of deportees began. Deportees who escaped the gas chambers and were considered fit for work were tattooed.
The Nazis believed that this was the best way to identify all prisoners given the vastness of the camp, which with its 47 annexes had an area of 40 square kilometres.
Tattooing prisoners was part of a system designed to dehumanise them. Prisoners had to memorise their identification number and had to be able to recite it in German.
It was a further offence to religious Jews who are forbidden by the Torah from altering the body.
About 400,000 prisoners were registered and reduced to a single number in the largest Nazi extermination camp. More than half of them perished.
In total, around 1.1 million people died at Auschwitz.
Over 90% of the victims were Jews.