The number of Holocaust survivors globally has shrunk to 220,000 on the 80th anniversary of the liberation of Auschwitz-Birkenau, according to a new estimate. Why it matters: The anniversary, which also commemorates International Holocaust Remembrance Day on Monday,

Ruth Cohen, a 94-year-old American Holocaust survivor, returned to the Auschwitz concentration camp in Poland for the first time. She recalled seeing family members before they were separated for the last time at the camp.

Survivors of the Nazi's notorious Auschwitz death camp are taking center stage at the memorial service to mark 80 years since its liberation by Soviet troops.