World War I

June 28, 1914 - Archduke Franz Ferdinand of Austria and his wife Sophie are assassinated in Sarajevo; this is the casus belli of World War I (Source)

Recommended sermons and podcasts:

The following messages on World War I are by Dr. Peter Hammond:

Did You Know These Facts About the First World War?
The Clash of Civilizations and the Forces Behind the Great War
Assassination in Sarajevo
Evaluating the Propaganda of the Great War
Evaluating Hollywood Films on World War I
Versailles - 100 Years Ago
The Christmas Truce

Recommended videos:

Snoopy and the Red Baron, by The Royal Guardsmen
Snoopy's Christmas Vs. the Red Baron, by The Royal Guardsmen