Disaster struck the world 100 years ago this week, leading to millions of deaths, wrecking cities, ripping old nations apart and creating new ones, overturning empires and the monarchs that led them, sweeping away traditional customs and values, and changing the world in ways that still affect us today.
On July 28, 1914, the Austro-Hungarian Empire declared war on the tiny nation of Serbia. Within a few days, the world's greatest powers were at each other's throats.
Thus began the Great War, or as we now remember it, World War I.
The centenary has been generating new books, news stories and analyses. But why should we care about something that happened a century ago?
Because in many ways, the world we live in is a product of World War I.