On June 28th, 1914, Franz Ferdinand was parading in the town of Sarajevo, Bosnia with his wife Sophie. They were warned that the Black Hand, and many others were going to attempt to kill Franz, but they still decided to go.
As predicted, the Black Hand had sent out 6 assassins, and deployed them on Appel Quay. Black Hand was powerful, and equipped these men with a pistol and two bombs each. Two of them failed to act, but when Franz passed by Nedeljko Čabrinović, he didn't hesitate, and threw his bomb.
The bomb missed, and exploded right underneath the next car due to the timing of bomb. Franz sped away, knowing of the risk now. It had injured the passengers of the car behind them, and delayed the other cars slightly, causing a massive change in the atmosphere of the parade.
But once he had finished a visit to the Town Hall, and said his speeches, he and his wife decided to go visit the wounded at the hospital. No one explained the new route to the driver. They headed out with as much protection as possible.
The driver ended up turning right into Franz Joseph st, where Gavrilo Princip was standing, ready to kill, following the old route. He was told to hit reverse, but Princip didn't hesitate, and shot two shots, one hitting Sophie, and the other hitting Franz.
Princip was arrested immediately as the couple were rushed to medical help. Sophie died before arriving, and Franz died 10 minutes after that. His last words were "Sophie, Sophie! Don't die, live for our children!". And that, was the spark that possibly started WW1.