Auschwitz concentration camp (German: Konzentrationslager Auschwitz (pronounced [kntsntatsionsla avts] (listen)); also KL Auschwitz or KZ Auschwitz) was a complex of over 40 concentration and extermination camps operated by Nazi Germany in occupied Poland (in a portion annexed into Germany in 1939) during World War II and the Holocaust. It consisted of Auschwitz I, the main camp (Stammlager) in Owicim; Auschwitz II-Birkenau, a concentration and extermination camp with gas chambers; Auschwitz III-Monowitz, a labor camp for the chemical conglomerate IG Farben; and dozens of subcamps. The camps became a major site of the Nazis' final solution to the Jewish question.

After Germany sparked World War II by invading Poland in September 1939, the Schutzstaffel (SS) converted Auschwitz I, an army barracks, into a prisoner-of-war camp.The initial transport of political detainees to Auschwitz consisted almost solely of Poles for whom the camp was initially established. The bulk of inmates were Polish for the first two years.In May 1940, German criminals brought to the camp as functionaries, established the camp's reputation for sadism. Prisoners were beaten, tortured, and executed for the most trivial reasons. The first gassingsof Soviet and Polish prisonerstook place in block 11 of Auschwitz I around August 1941. Construction of Auschwitz II began the following month, and from 1942 until late 1944 freight trains delivered Jews from all over German-occupied Europe to its gas chambers. Of the 1.3 million people sent to Auschwitz, 1.1 million were murdered. The number of victims includes 960,000 Jews (865,000 of whom were gassed on arrival), 74,000 ethnic Poles, 21,000 Roma, 15,000 Soviet prisoners of war, and up to 15,000 other Europeans. Those not gassed were murdered via starvation, exhaustion, disease, individual executions, or beatings. Others were killed during medical experiments.

At least 802 prisoners tried to escape, 144 successfully, and on 7 October 1944, two Sonderkommando units, consisting of prisoners who operated the gas chambers, launched an unsuccessful uprising. Only 789 Schutzstaffel personnel (no more than 15 percent) ever stood trial after the Holocaust ended; several were executed, including camp commandant Rudolf Hss. The Allies' failure to act on early reports of atrocities by bombing the camp or its railways remains controversial.

As the Soviet Red Army approached Auschwitz in January 1945, toward the end of the war, the SS sent most of the camp's population west on a death march to camps inside Germany and Austria. Soviet troops entered the camp on 27 January 1945, a day commemorated since 2005 as International Holocaust Remembrance Day. In the decades after the war, survivors such as Primo Levi, Viktor Frankl, and Elie Wiesel wrote memoirs of their experiences, and the camp became a dominant symbol of the Holocaust. In 1947, Poland founded the Auschwitz-Birkenau State Museum on the site of Auschwitz I and II, and in 1979 it was named a World Heritage Site by UNESCO.

A diary is a record (originally in handwritten format) with discrete entries arranged by date reporting on what has happened over the course of a day or other period. A personal diary may include a person's experiences, thoughts, and/or feelings, excluding comments on current events outside the writer's direct experience. Someone who keeps a diary is known as a diarist. Diaries undertaken for institutional purposes play a role in many aspects of human civilization, including government records (e.g. Hansard), business ledgers, and military records. In British English, the word may also denote a preprinted journal format.

Today the term is generally employed for personal diaries, normally intended to remain private or to have a limited circulation amongst friends or relatives. The word "journal" may be sometimes used for "diary," but generally a diary has (or intends to have) daily entries (from the Latin word for 'day'), whereas journal-writing can be less frequent.Although a diary may provide information for a memoir, autobiography or biography, it is generally written not with the intention of being published as it stands, but for the author's own use. In recent years, however, there is internal evidence in some diaries (e.g. those of Ned Rorem, Alan Clark, Tony Benn or Simon Gray) that they are written with eventual publication in mind, with the intention of self-vindication (pre- or posthumous), or simply for profit.

By extension, the term diary is also used to mean a printed publication of a written diary; and may also refer to other terms of journal including electronic formats (e.g. blogs).