Summary: The Concert of Europe held the continent together for years after the Napoleonic Wars, but as the leadership of great nations weakened over time, the stage was set for a colossal tragedy.

Summary: When Archduke Franz Ferdinand of Austria decided to visit Serbia on a day of national pride, he angered young nationalists like Gavrilo Princip and touched off the series of events that tumbled the world into war.

Summary: In the wake of Franz Ferdinand's assassination, the great powers of Europe scramble to find an answer to the looming threat of war. While Germany urges Austria-Hungary to resolve the matter quickly, Russia begins to mobilize its forces to defend the slavic state of Serbia. A handful of people across the nations recognize the danger and do their best to stop it.

Summary: Serbia responds to Austria-Hungary's ultimatum after the assassination of Archduke Franz Ferdinand, and the pretext for war grows thinner and thinner. Caught between a rock and a hard place, Austrian Foreign Minister Leopold Berchtold makes a desperate decision to declare war. Kaiser Wilhelm of Germany and Czar Nicholas II of Russia call upon their family ties to each other in a last ditch effort to avert the war, but their previous inattention has left their prime ministers Bethmann-Hollweg and Sazonov in impossible positions. With their forces mobilized, unable to back down, Russia must accept Germany's declaration of war from ambassador Pourtalès - and as our series ends, the Seminal Catastrophe begins.

Summary: The search for truth in history is always a matter of blazing a path through multiple sources, each with a different perspective. We hope this series about the events that lead to World War I not only taught you new things, but encouraged you to ask new questions. Our writer, James Portnow, sits down to talk about what he learned from researching and writing this series - as well as the mistakes we made along the way. Did the world really hinge on Gavrilo Princip's sandwich? How do we know so much about Russian Foreign Minister Sergei Sazonov's day? We answer these questions and more, but above all, we encourage you to do more research on your own!