The International Date Line runs down the middle of the Pacific Ocean. If you cross the date line moving east, you subtract a day, whereas if you are moving west you add a day. For example, if today is Friday and we crossed the International Date line from west to east then it would be Thursday.
Moreover, what is the purpose of the international date line?
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.
What countries are on the international date line?
It is not a perfectly straight line and has been moved slightly over the years to accommodate needs (or requests) of varied countries in the Pacific Ocean. Note how it bends to include all of Kiribati, Samoa, Tonga and Tokelau in the Eastern Hemisphere.