World leaders gathered at Auschwitz last month to mark the liberation 70 years earlier of the Nazis’ most infamous concentration camp. More ceremonies will follow in coming months to remember the Allied forces’ discovery, in rapid succession, of other Nazi concentration camps at places like Bergen-Belsen that winter and spring of 1945.

Largely lost to history, however, is the cruel reality of what “liberation” actually meant for hundreds of thousands of Holocaust survivors discovered barely alive in the Nazi camps.

Even after the victorious American and Allied forces took control of the camps, the survivors — mainly Jews, but also small numbers of gays, Roma, Communists, Jehovah’s Witnesses and others — remained for months behind barbed wire and under armed guard in what became known euphemistically as displaced persons, or D.P., camps. Many Jews were left wearing the same notorious striped pajamas that the Nazis first gave them.

With the American forces overwhelmed by the sheer numbers of refugees under their control, underfed survivors lived for months in decrepit camps in Germany and Austria — a number of them on the same grounds as the concentration camps. Even after conditions improved, thousands of former prisoners remained inside and in limbo for as long as five years because the United States and most other nations refused to let them in.

In the early months after the war, thousands of survivors died from disease and malnutrition. Food was so scarce that rioting broke out at some camps, as Allied commanders refused to give extra food rations to Jewish survivors because they did not want to be seen as giving them preferential treatment over German P.O.W.s and other prisoners....