If you like the idea of standard time zones, you can thank the railroads for that. Today is the anniversary of the first implementation of standard time zones on November 18, 1883.
As a result, the railroads introduced four time zones across the United States. All locations in that zone would share the same time and there would be an hour difference between those zones. This idea was quickly adopted by the public but Congress wouldn't make it a law for another 35 years.
The railroads were also responsible for introduce more accurate and reliable timepieces. A rail industry committee was responsible for setting the standards for this timepieces and they were made of the best materials at the time. It was also mandated that railroad operators keep their timepieces to within 30 seconds of a standard time.
Currently the official time is regulated by the National Institute of Standards and Technology (NIST) via an atomic clock. This clock is so accurate it is estimated it will lose 1 second every 100 million years. If you are interested in the official time you can go to time.gov. If you have a shortwave radio, you can listen to 5, 10 or 15,000 kHz to WWV (or WWVH if you are close to Hawaii).