The first mechanical clock
Around 1275, an Italian monk designed the first mechanical clock. The clock was driven by the slow pull of a falling weight, basically like a very big hour hand. The world’s oldest working clock (pictured) was built in 1386 and is still ticking away at Salisbury Cathedral, UK. Like all clocks of that time it has no face but strikes the hour on a bell. Today, the International Atomic Time, kept by 300 atomic clocks around the world, keeps earth’s time to within microseconds of accuracy of solar time. However, since the rotation of earth is slightly irregular and slowing down slowly, a leap second has to be added occasionally, giving us the world standard time known as Coordinated Universal Time (UTC). If all of the above left you scared, you probably suffer from chronophobia, the phobia of time. If you don’t mind the time but suffer from chronomentrophobia, the fear of clocks, head out to Las Vegas: there are no clocks in the gambling casinos.