Kragujevac ( , ) is the fourth largest city in Serbia and the administrative centre of the Šumadija District . It is the historical centre of the once densely-forested region of Šumadija in central Serbia , and is situated on the banks of the Lepenica River . , the city proper has a population of 150,835 , while its administrative area comprises a total of 179,417 inhabitants . Kragujevac was the first capital of modern Serbia and the first constitution in the Balkans , the Sretenje Constitution , was proclaimed in the city in 1838 . During the Second World War , Kragujevac was the site of a massacre by the Nazis in which 2,778 Serb men and boys were killed
massacre by the Nazis
Kragujevac massacre
Kragujevac