Our 24-hour day starts at 12 midnight. Because of the earth’s rotation, the midnight occurs at different times, at different places.
As the Earth is spherical in shape, every place has a place to its East.
So, it was necessary to determine at what location to the East does the day start on Earth.
Hence, representatives of many nations got together, under the leadership of an American Professor, Davidson, in the year 1884 and decided the International Date Line.
The line was drawn opposite to the Greenwich Prime Meridian i.e. with reference to the 180° Meridian.
