Royal Greenwich Observatory was established in 1675 by order of Charles II. The building has significant historical and scientific connections. Today’s Prime Meridian goes through the property. Greenwich Mean Time was calculated there until 1954. Today the building is a tourist attraction.
Prime Meridian was formally agreed to in 1884. Twenty-five countries met to establish uniform lines of longitude and resulting time zones. Prior to the agreement, fourteen different prime meridians were recognized. The Prime Meridian and other lines of longitude, as well as lines of latitude, help us know where we are on earth and where we are in relation to others.
World Standard Time was accomplished in 1884. The International Meridian Conference met in Washington, DC. The group established the Prime Meridian through Greenwich and established 24 time zones. Prior to that conference, different countries used different times. In the United States, different railroads used different time systems. It was all very confusing! Children can find the time in different cities world wide at: World Clock.