What is International Date Line?
[[image:Time Zones Small (2007).jpg|260px|thumb|right|Jagged red line down the right is the International Date Line]] [[Image:International Date Line.png|thumb|The International Date Line around 180°]] The '''International Date Line''' (IDL), also known as just the Date Line, is an imaginary line on the surface of the [[Earth]], going from north to south in the [[Pacific Ocean]]. The date becomes one day later as one travels across it in western direction, and one day earlier as one travels across it in eastern direction. The reason for this effect is that the countries on the western side of the International Date Line, (in or outside eastern Asia) have the [[time zone]] 10–12 hours more than [[Greenwich]]. And the countries on eastern side of it (Alaska/Hawaii and other areas) have the [[time zone]] 9–12 hours less than [[Greenwich]]. So when travelling across the line, one's watch has to be adjusted 20–24 hours, depending on the time zones. For example, [[New Zealand]] is twelve hours ahead of [[Greenwich Mean Time]] while [[Hawaii]] is ten hours behind [[Greenwich Mean Time]]. When travelling from New Zealand to Hawaii the clocks must be switched 22 hours backwards, about one day. ==Geography== International Date Line follows the [[Meridian (geography)|meridian]] of [[180°E longitude|180° longitude]] down the middle of the [[Pacific Ocean]] for some distance. So that it does not cross nations, it passes around the far east of [[Russia]] and other [[archipelago]]s in the Pacific. In the north the date line turns to the east through the [[Bering Strait]] and then west past the [[Aleutian Islands]] in order to keep [[Alaska]] and Russia on opposite sides of the line. This is to keep it in agreement with the date of the rest of those countries. The date line passes equidistantly between the two [[Diomede Islands]]—[[Little Diomede Island]] (US) and [[Big Diomede Island]] (Russia)—at a distance of 1.5&nbsp;km (1&nbsp;mi) from each island. The date line [[circumvent]]s the territory of [[Kiribati]] by swingin