International Date Line

The imaginary line where today becomes tomorrow/Infrastructure

The International Date Line (IDL) is an imaginary line running roughly along the 180th meridian in the Pacific Ocean, where the calendar date changes by one day. Traveling westward across the line advances the date by one day; traveling eastward sets it back. While conceptually straight, the actual line zigzags to avoid splitting countries and island groups into different dates. It was established by international agreement in 1884 at the International Meridian Conference in Washington, D.C. The line passes through no major landmass, traversing mostly open ocean from the Arctic to the Antarctic.