Where is Prime Meridian?
The meridian that passes through Greenwich, England is called Prime Meridian. The eastern part of the earth to the prime meridian is called the eastern hemisphere whereas the western part is known as the western hemisphere.
When the sun in Greenwich is at the highest point in the sky, all places along this meridian will have mid-day or noon. Prime meridian helps in determining the time zone of the countries. The time increases at the rate of four minutes per one degree of longitude.