Answer
**Unflinching detail** characterized the Vrba-Wetzler report, a crucial document in exposing the horrors of Auschwitz and other Nazi concentration camps during World War II. Rudolf Vrba and Alfred Wetzler, two Slovak Jews who escaped the Auschwitz camp in April 1944, meticulously compiled this firsthand account. The report provided explicit information on the systematic extermination of Jews, including the existence of gas chambers and the scale of mass killings.