Halloween
The festival of Halloween, on 31st October, takes place in lots of countries around the world but is mostly celebrated in the USA. Children dress up as scary characters and have parties and celebrations.
Trick-or-Treating
One Halloween custom is to go from house to house in small groups “Trick-or-Treating”. Neighbours choose a trick or a treat. If they choose a treat, they have to give the Trick-or-Treaters some kind of treat; usually sweets. The children play tricks on the neighbours who don’t give them a treat.
Trick-or-Treat for UNICEF
For more than sixty years children have helped to raise money for UNICEF* by
Trick-or-Treating. Children ask for money instead of sweets and at the end of the day they send all of the money to UNICEF to help children in poor countries. It pays for medicine, food, clean water and education. Since the project began, UNICEF has collected $123 million. Last year they raised $4 million and this year they hope to raise more.
The origins of the idea
On October 31st 1947 a minister named Reverend Clyde Allison and his family had the idea to raise money for UNICEF by Trick-or-Treating. The following year school groups, police and fire departments and all kinds of other groups joined in.
Around the world
By 1960, Trick-or-Treat for UNICEF activities had spread to many countries around the world including Canada, Japan, and Spain. Celebrities and politicians supported the activities and in 1967, US President Johnson declared Halloween as “National UNICEF Day”.

*UNICEF: United Nations International Children's Emergency Fund


Source: http://youth.unicefusa.org/trickortreat/