Before trains, every town kept its own time — and it caused chaos

For most of human history, time was local. Each town set its clocks by the sun: when it reached its highest point overhead, that was noon. This meant a village 15 miles east might run its clocks a few minutes ahead of its neighbor, and nobody minded — you couldn't travel fast enough for the difference to matter.

Then came the railway. Trains moved people across long distances in hours, and schedules built on hundreds of slightly different local times became a nightmare. A single rail line could pass through dozens of 'noons.' Worse, mismatched clocks caused deadly collisions when two trains thought they had the track to themselves. British railways began imposing a single 'railway time' in the 1840s, decades before governments made it official.

The global fix arrived in 1884, when delegates at the International Meridian Conference in Washington, D.C., agreed to divide the planet into standard time zones anchored to the Greenwich Meridian. Canadian engineer Sandford Fleming was a driving force behind the idea of splitting the world into 24 hourly slices.

So the tidy grid of time zones we take for granted wasn't born from astronomy or philosophy — it was an engineering patch to keep trains from crashing.