This is fresco of innocent Serbs killed during Ustasa genocide in Second World War.
Those victims are canonized as saints, and celebrated in Serbian Orthodox Church.
On the ribbon carried by the angels, you can read names of some of the historical places of massacre.
Kosovo i Metohija, Banjica, Jasenovac, Prebilovci, Jadovno, Jasenovac, Kragujevac, Glina, Kraljevo