How did Allied soldiers discover Nazi concentration camps at the end of World War II?

In the final months of World War II, as Allied armies advanced into Germany and Austria, they encountered Nazi concentration camps while en route to military targets. By the winter of 1944–45, SS officials had attempted to conceal their crimes by forcibly evacuating prisoners westward in "death marches," leaving behind evidence of the atrocities that had occurred.1

When American and British forces entered these camps in April and May 1945, they were confronted with horrific conditions, including mass graves, emaciated survivors, and, at sites like Dachau, railway cars filled with decomposing bodies. The British army liberated Bergen-Belsen on April 15, 1945, where they were forced to bury thousands of corpses to prevent the spread of typhus.21

These discoveries left an indelible impression on the soldiers, who were tasked with healing the sick and burying the dead. The subsequent publication of photographs and newsreel footage by Western media profoundly shaped the public’s understanding of the Holocaust, bringing global attention to the Nazi regime's crimes.123