Armenia

Longterm and dormant, dating back to 1915-17. 
 
The Armenian Holocaust or Great Calamity occurred during the incremental fall of the Ottoman empire in WW1. Around 600,000 (perhaps up to 1.5m) Armenians were killed and more deported.
 
During the shrinkage of the Ottoman empire, Turks attempted to eliminate the Armenians (also Assyrians and Greeks), who were prominent, second-class citizens by dint of their Christian faith. Property was seized, thousands murdered and raped, others exiled through the desert to Syria – in many cases the dirty work was done by Kurds, desperate to curry favour for a homeland of their own.
 
This disaster has never been resolved. Turkey denies the genocide, and other nations remain quiet to this day. Inactive, this conflict nevertheless simmers quietly, a possible cause of future conflict.
 

LINKS:

Armenian National Institute
Wikipedia: Armenian Genocide
Armeniapedia
Armenian Genocide
United Human Rights Council