What specific event started World War I?

The first world war began in August 1914. It was directly triggered by the assassination of the Austrian archduke, Franz Ferdinand and his wife, on 28th June 1914 by Bosnian revolutionary, Gavrilo Princip.

the answer is: the sesquicentennial of the american civil war is an occasion to consider the legacy of that great conflict. this legacy is our inheritance, and despite many indelible features, we continue to negotiate the resolution of that conflict. the civil war was fought over slavery, but not always on behalf of slaves

theodore roosevelt challenged william to a duel, whoever won, got their policy sent to congress. it ended up in a stalemate, and both men were injured and sent to the hospital.