Children's day is recognized on various days in many places around the world. Children's Day began the second Sunday of June in 1856 by the Reverend Dr. Charles Leonard, pastor of the Universalist Church of the Redeemer in Chelsea, Massachusetts. That Sunday Dr. Leonard held a special service just for children. Dr. Leonard christened the day, Rose Day. Later it was named Flower Sunday. However, later the second Sunday of the month of July was named Children's Day.
The International Protection of Children Day has been observed in many countries as Children's Day on June 1st since 1950. It was established by the Women's International Democratic Federation on its congress in Moscow (November 4th 1949). The Universal Children's Day is celebrated on November 20th, by the United Nations' recommendation. It takes place annually and it was first proclaimed by the United Kingdom in 1954. It was established to encourage all countries to institute a day to promote understanding amongst children and also to promote the welbeing of children all around the world.
To find out when Children's Day is celebrated all around the world go to Children's Day
Source: Children's Day