Franz Ferdinand was an Archduke of Austro-Hungary and heir to the Austro-Hungarian throne. The Archduke was assassinated in Sarajevo (Capital City of Bosnia) alongside his wife, Sophie, on June 28th, 1914 by Gavrilo Princip, a Bosnian-Serb revolutionary. (June 28th happened to be their marriage anniversary.) This is often attributed as being the cause of World War One. The Archduke's death sent off a chain of events that caused the Great War. Austria-Hungary blamed Serbia for Ferdinand's death, and declared war. This led to the Russians supporting Serbia because of their Alliance Pact. After that, Germany supported Austria-Hungary. Then after that... France joined their allies the Russians... then Britain joined their allies France and Russia... and so on until Europe was fairly evenly divided and ready for war. War was declared on July 28, 1914.
Here is an image of his residence, the Castle Konopiste. This castle was built in the 1280's as a Gothic fortification. Ferdinand purchased it in 1887 and had it renovated. He kept about 100,000 trophies from his love of hunting here at Konopiste. The Castle is now essentially a museum to dedicated to the history of medieval life and the life Franz Ferdinand.
Archduke Franz Ferdinand will be forever remembered as the ultimate cause of the First World War. His assassination directly led to the escalation of events that caused the Great War. World War I was known as "The War To End All Wars" which it did not, unfortunately, do, but it just shows how great and terrible it was. Just recently, Germany finally repaid all of its war debts from this war, taking about an entire century!
William Cavendish-Bentinck, Sixth Duke of Portland
William Cavendish-Bentinck, the Sixth Duke of Portland (In Britain) recounted in his book Men, Women, and Things "One of the loaders fell down. This caused both barrels of the gun he was carrying to be discharged, the shot passing within a few feet of the archduke and myself. I have often wondered whether the Great War might not have been averted, or at least postponed, had the archduke met his death there and not at Sarajevo the following year." Essentially, what he is saying is that World War I could have potentially been completely avoided by a sheer chance accident. I'm not saying that I would have preferred for the Archduke to have been killed in an accident, but it potentially could have completely stopped the Great War before it had even started.
There is a rock band named after him that is still making music to this day.