Where is all time measured from?
I assume what you're asking has to do with time zones and where the "central" time zone is that all others refer to. If so, then the answer is Greenwich, England.
When time zones were first being standardized, the Royal Observatory for the United Kingdom was at Greenwich, which is now part of London. This happened in the 1870s, when Great Britain was the most powerful nation in the world. Because it was the most powerful nation everyone else followed its lead and Greenwich became the reference point.
The time at Greenwich is known as Greenwich Mean Time or Coordinated Universal Time.