In the numerous "killing fields" all across the country of Cambodia. The genocide did not happen in just one place. Probably the most important and most famous killing field is Cheung-Ek, which is around 15-30 minutes outside of the capital Phnom Penh.
Cambodia
Which genocide? if you're talking about the holocaust, it took place in the 1940s
The Bosnian genocide took place in Bosnia.
Guatemala
The film The Killing Fields took place in Cambodia. Much of it was in Cambodia's capital, Phnom Penh.
1915 to 1918
In Rwanda.
Genocide has taken place throughout history and has been done to many different races and nationality's
Between April to July 1994.
In Guatemala between 1981 & 1983
Genocide happens because people believe that they have the right to assert their superiority over others and take their belongings and lives.