People sometimes refer to a battlefield or a place where many people have been killed as that place's killing fields.
...the killing fields of Rwanda.
killing fields in British English
(ˈkɪlɪŋ fiːldz)
plural noun
a place where a lot of people have died, usually as a result of war or civil unrest
This visit to the Holocaust killing fields by the cemetery in Domachevo was the firsttime a British jury has travelled abroad to the scene of the crime.