Memorial Day, originally known as Decoration Day, started just a few years after the Civil War.  The Veterans Unions wanted to remember their fallen soldiers by decorating their graves at the Arlington Cemetary and other cemetaries across the country with flowers. 

However, it wasn't until 1971 when Congress made "Memorial Day" a national holiday honoring soldiers of all wars.  For the full report on the history of Memorial Day, visit the U.S. Department of Veteran Affairs website at http://www1.va.gov/opa/speceven/memday/history.asp.