Following the outbreak of World War II and the invasion of Yugoslavia in 1941, Republika Srpska fell under the rule of the Nazi puppet state, The Independent State of Croatia. Around 300,000 Serbs are estimated to have died under the Ustashe regime as a result of their genocide campaign; a slew of massacres, as well as the use of a variety of concentration and extermination camps, took place in Republika Srpska during the war. The Jasenovac concentration camp, located in modern-day Croatia, was the site of the deaths of some 100,000 people, about 52,000 of which were Serbs. Massacres also occurred at Garavice and Kruščica concentration camp in the eastern part of Bosnia. The regime systematically and brutally massacred Serbs in villages in the countryside, using a variety of tools. The scale of the violence meant that approximately every sixth Serb living in Bosnia-Herzegovina was the victim of a massacre and virtually every Serb had a family member that was killed in the war, mostly by the Ustaše. The experience had a profound impact in the collective memory of Serbs in Croatia and Bosnia. An estimated 209,000 Serbs or 16.9% of its Bosnia population were killed on the territory of Bosnia–Herzegovina during the war. Today, monuments honouring these victims can be found across Republika Srpska and Bosnia and Herzegovina.