Question: What is the name of this series of mass executions during World War II, which, along with Sambor Ghetto, was anenexed to the Ukranian SSR?
Context: List of mass executions and massacres in Yugoslavia during World War II Skæring Hede (Skæring Heath) or Skæring Mindelund (Skæring Memorial) is a forest and memorial park in Skæring, the northernmost suburb of Aarhus, Denmark.  Skæring Hede was originally a large heath but today only a fraction of it remains as encroaching suburbs and areas with summer houses have gradually taken over much of the natural land in the area, through the 70s and 80s.  The remaining area of 8.5 ha are mainly forest, although some heath do remain, and is managed as a public forest park by Aarhus Municipality.  Today Skæring Hede is one of only a few public forests in Skæring and the northernmost park in Aarhus.  The forest is mainly mixed pine and birch forest with a number of walking paths crossing through it and it is home to a World War II memorial.  Skæring Hede is well known as the place where five Danish resistance fighters were executed during the Second World War in one of the first mass executions during the war.  Parking facilities on "Åstrup Strandvej". Carl-Heinrich von Stülpnagel (2 January 1886 – 30 August 1944) was a German general in the Wehrmacht during World War II who was an army level commander.  While serving as military commander of German-occupied France and as commander of the 17th Army in the Soviet Union during Operation Barbarossa, Stülpnagel was implicated in war crimes, including authorising reprisal operations against civilian population and closely cooperating with the Einsatzgruppen in their mass executions of Jews. The NKVD prisoner massacres were a series of mass executions carried out by the Soviet NKVD secret police during World War II against political prisoners across Eastern Europe, primarily Poland, Ukraine, the Baltic states, Bessarabia and other parts of the Soviet Union from which the Red Army was retreating following the Nazi German attack on the Soviet positions in occupied Poland, known as Operation Barbarossa. The Warsaw Ghetto Uprising (Yiddish: אױפֿשטאַנד אין װאַרשעװער געטאָ‎ ; Polish: "powstanie w getcie warszawskim" ; German: "Aufstand im Warschauer Ghetto" ) was the 1943 act of Jewish resistance that arose within the Warsaw Ghetto in German-occupied Poland during World War II, and which opposed Nazi Germany's final effort to transport the remaining Ghetto population to Treblinka.  The uprising started on 19 April when the Ghetto refused to surrender to the police commander SS-Brigadeführer Jürgen Stroop, who then ordered the burning of the Ghetto, block by block, ending on 16 May.  A total of 13,000 Jews died, about half of them burnt alive or suffocated.  German casualties are not known, but were not more than 300.  It was the largest single revolt by Jews during World War II. The massacres in Piaśnica were a set of mass executions carried out by Nazi Germany during World War II, between the fall of 1939 and spring of 1940 in Piaśnica Wielka (Groß Piasnitz) in the Darzlubska Wilderness near Wejherowo.  The exact number of people murdered is unknown, but estimates range between 12,000 and 14,000 victims.  Most of them were Polish intellectuals from Gdańsk Pomerania, but Poles, Jews, Czechs and German inmates from mental hospitals from General Government and the Third Reich were also murdered.  After the Stutthof concentration camp, Piaśnica was the largest site of killings of Polish civilians in Pomerania by the Germans, and for this reason is sometimes referred to as the "second" or "Pomeranian" Katyn.  It was the first large scale Nazi atrocity in occupied Poland. The Łuck Ghetto (a.k.a. the Lutsk Ghetto, Polish: "getto w Łucku" , German: "Ghetto Luzk" ) was a Jewish World War II ghetto established in 1941 by the "Schutzstaffel" ("SS") in the prewar Polish city of Łuck (now Lutsk, Ukraine) occupied by Germany after Operation Barbarossa, in the south-eastern region of Kresy.  Łuck was the capital of the Wołyń Voivodeship (1921–39) in the Second Polish Republic before the joint Nazi-Soviet invasion of Poland of 1939.  The invading Soviets annexed the city to the Ukrainian SSR in 1939 along with the entire region, an renamed it as Луцьк (Lutsk). Stanisławów Ghetto (Polish: "getto w Stanisławowie" , German: "Ghetto Stanislau" ) was a Jewish World War II ghetto established in 1941 by the "Schutzstaffel" ("SS") in the prewar Polish city of Stanisławów in the south-eastern region of Kresy (now Ivano-Frankivsk, Ukraine) occupied by Germany after Operation Barbarossa.  Before the joint Nazi-Soviet invasion of Poland in 1939 Stanisławów was the capital of the Stanisławów Voivodeship in the Second Polish Republic.  The Soviets annexed the city to the Ukrainian SSR in 1939 along with the entire region, but renamed it as Ivano-Frankivsk in 1962, long after the war ended.  In 1941 Stanisławów (then, Stanyslaviv) was overrun again, this time by the Wehrmacht army, in the course of the German attack on the Russian positions behind the Curzon Line (see map, marked in red), and incorporated it into their own "Distrikt Galizien", as the fifth district of the "Generalgouvernement". The Częstochowa Ghetto was a World War II ghetto set up by Nazi Germany for the purpose of persecution and exploitation of local Jews in the city of Częstochowa during the German occupation of Poland.  The approximate number of people confined to the ghetto was around 40,000 at the beginning and in late 1942 at its peak – right before mass deportations – 48,000.  Most ghetto inmates were delivered by the Holocaust trains to their deaths at the Treblinka extermination camp.  In June 1943, the remaining ghetto inhabitants launched the Częstochowa Ghetto uprising, which was extinguished by the "SS" after a few days of fighting. Sambor Ghetto (Polish: "getto w Samborze" ) was a Jewish World War II ghetto established in March 1942 by the "Schutzstaffel" ("SS") in the prewar Polish city of Sambor in the south-eastern region of Kresy (now Sambir, Ukraine).  Sambor was occupied by Nazi Germany twice, first during the joint German-Soviet invasion of Poland in 1939, and again, after the 1941 Operation Barbarossa.  Before the war, Sambor was a county seat in the Lwów Voivodeship of the Second Polish Republic.  The invading Germans handed the town over to the Soviets in accordance with the Nazi-Soviet Pact against Poland.  Sambor was annexed to the Ukrainian SSR along with the entire region in the atmosphere of intimidation, and the NKVD terror.  In 1941 the city was overrun again by the Wehrmacht army in the course of the German attack on the Soviet positions behind the Curzon Line (see map, marked in red), and incorporated it into their own "Distrikt Galizien".  According to the Polish census of 1931 Jews constituted nearly 29 percent of the town's inhabitants, most of whom were killed during the Holocaust.  Sambor (Sambir) is not to be confused with the much smaller Old Sambor (Stary Sambor, now Staryi Sambir) located close-by, although their Jewish history is inextricably linked together.
Answer: NKVD prisoner massacres