March 20’s history turns on moments when established arrangements are challenged or abruptly reshaped. In 1815, Napoleon Bonaparte returned to Paris after escaping exile on Elba, reclaiming power and launching the brief, turbulent period called the Hundred Days. In 1854, a gathering in Ripon, Wisconsin, helped establish the Republican Party as a major political force opposed to slavery. These events unfolded in very different arenas, but each speaks to the uncertain balance between authority and opposition—and to how quickly political landscapes can change.
The day also links cultural change with modern catastrophe. Henrik Ibsen, born in 1828, would become a defining voice in modern theater, using works such as *A Doll’s House* to confront the moral expectations of his time. More than a century later, the 1995 sarin attack on Tokyo’s subway brought deadly violence into the routines of morning commuters. Together, these entries range from debates over social norms to the vulnerability of public spaces. Falling near the March equinox, March 20 also sits at a seasonal hinge in the Northern Hemisphere: a fitting backdrop for a list marked by transitions, though its turning points are political, artistic, and tragic rather than natural.