The International Date Line, established in 1884, passes through the mid-Pacific Ocean and roughly follows a 180 degrees longitude north-south line on the Earth. It is located halfway round the world from the prime meridian—the zero degrees longitude established in Greenwich, England, in 1852.

Where does the international date line start and end?

The international date line is an imaginary north-south line drawn through the middle of the Pacific Ocean about half way around the world, close to the 180 degrees of longitude from the Prime Meridian, which cuts through Greenwich, England.

Where does the day starts first in the world?

Each day on Earth begins at midnight in Greenwich, England, where the prime meridian is located. Originally, the prime meridian's purpose was to help ships at sea find their longitude and determine accurately their position on the globe.