Missing Sons: A century of grieving

World War I is equated with mass destruction like no other war before it. Highly industrialized nations were able to produce large quantities of weapons, including lethal gas. The German soldiers in this picture are waiting for a poison gas attack, but the flying dove above their heads is a sign that the threat is still far away.

The staggering power of heavy artillery meant that dead bodies were mutilated to an unrecognizable state and people simply vanished somewhere in the middle of a battlefield far from home. The exhibition shows how World War I - with its 10 million casualties - changed the way people grieved loved ones they could not bury.

The ossuary at the Verdun memorial site in France contains the remains of 130,000 unknown French and German soldiers. It is an irony of history: In death, the bones of the former enemies are inseparably connected forever.

Peter Kollwitz was 18 years old when he fell in battle in Flanders, Belgium, in October 1914. His mother, the German sculptress Käthe Kollwitz, depicted the mourning of her son in her art many times in until her own death in 1945.

The grieving parents did not have graves to visit. All they were left with were lists with the names of the fallen. That’s why military cemeteries were built as mourning sites. The picture shows Peter Kollwitz's tombstone of in Vladslo, Belgium.

Rudyard Kipling was regarded as the most famous British writer in his day and was awarded the Nobel Prize for Literature. When World War I started, he encouraged his son to go to war - and regretted it for the rest of his life. His son John was announced missing in 1915 and his mortal remains were never found.

The picture shows the memorial to the victims of World War I at the Tyne Cot cemetery near Ypres in Belgium. The central memorial stones of the Commonwealth War Graves Cemeteries all have the same phrase written on them: "Their name liveth for evermore." The phrase was chosen by Rudyard Kipling.

The cult of names, which originated in World War I, became the blueprint for the mourning of millions of people whose lives have since been extinguished. The picture on the left shows the memorial at the so-called reloading point in Warsaw from which trains departed to concentration camps during the Holocaust. The picture on the right shows the Memorial de la Shoah in Paris.

The names of around 58,000 US soldiers who were killed in the Vietnam War have been engraved in the smoothly polished stone of the Vietnam War Veterans Memorial. The number of Vietnamese casualties of the war, which lasted from 1964 to 1975, amounts to millions.

During the Argentinean military junta, which lasted from 1976 to 1983, the people in power made tens of thousands of political enemies disappear. The mothers of the victims organized themselves and protested every Thursday in front of the presidential palace on the central Plaza de Mayo in Buenos Aires - until today. They still demand clarification regarding their children's destinies.

The picture shows an investigation team from the UN war crimes tribunal exhuming dozens of Muslim victims. In 1995, Serbs had killed around 8,000 boys and men and buried their bodies in these mass graves.

Half of the victims of the 9/11 terrorist attacks on the US disappeared without a trace. Bereaved people need a site where they can mourn - just as they did 100 years ago.