Complex sentence: Never Again is a common phrase used in relation to The Holocaust, it is also used in reference to the Armenian Genocide and is less commonly used in the same sense to refer to the Atomic bombings of Hiroshima and Nagasaki.
Split into simpler sentences: Never Again is a common phrase used in relation to The Holocaust. The phrase is also used in reference to the Armenian Genocide and, less commonly, the Atomic bombings of Hiroshima and Nagasaki.