The murder of Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, and his wife in Sarajevo in 1914 by a Bosnian Serb, Gavrilo Princip, 19, set the continent on a path to a war in which around 16 million people died.
Sarajevo closed the century under siege by Bosnian Serb forces during Yugoslavia's disintegration. Still dealing with the aftermath of this conflict, Bosnia's former warring communities marked the centennial deeply at odds over Princip's motives and his legacy.
Leaders of Serbia and the Bosnian Serbs, who consider the assassin a hero, boycotted the Sarajevo events, angered by what they say is an attempt to link the wars that opened and closed the 20th century, and to pin the blame on them.
They planned a dramatisation of the murder in the town of Visegrad, seared into the memory of Muslim Bosniaks for a wave of ethnic cleansing by Bosnian Serbs early in the 1992-95 war.
In Sarajevo, Austrian president Heinz Fischer was guest of honour at the concert in the restored City Hall, known as Vijecnica, where the archduke attended a reception on June 28, 1914. The archduke and his wife left in an open car, but the driver took a wrong turn and Princip took the opportunity to shoot them. The Austrians attacked Serbia a month later.
The neo-Moorish Vijecnica later became the National Library, and went up in flames in 1992 when attacked by Bosnian Serb forces. The building bears a plaque condemning the "Serb criminals" who fired the shells - a reference Serbian prime minister Aleksandar Vucic said prevented him from attending the concert. He was in Visegrad.
"This is a symbolic concert in a symbolic location," Professor Clemens Hellsberg, the orchestra's president and first violin, said. "We want to provide a vision of a common future in peace."
The programme for the concert - which was broadcast live on TV and radio stations - included work by Haydn, Schubert, Berg and Brahms.
Asked about the significance of a Vienna orchestra marking the event, conductor Franz Welser-Most said: "You should not deny the burden of history." The message, he said, was "never again".
For visitors to Sarajevo, guides offered tours of Princip's haunts and the key locations on the day he killed the archduke. Technicians prepared a midnight musical on the bridge near where he fired the fatal shot. Tourists milled around a replica of the car that carried the archduke to his death.
But some Sarajevans seemed bewildered by the fuss.
"Poor old Gavrilo should be left to history," said retired professor Leila Seleskovic. "Some praise him, others criticise him, but it's all a matter of century-old history."
Serbs see Princip as a freedom fighter, his shot bringing down the curtain on centuries of imperial occupation of the Balkans. That was the official narrative for decades under socialist Yugoslavia. But the collapse of their joint state shattered perceptions of Princip, whom many Bosniaks and Croats regard as a Serb nationalist with the same territorial ambitions as those behind much of the ethnic cleansing of the 1990s.
Bosnia was divided into two autonomous regions after the war, in a system of ethnic quotas that critics say has only cemented divisions.