What is the significance of Children's Day and carp streamers and helmets?

In Japan, May 5th is "Children's Day," a holiday to celebrate the growth and health of children. In the past, "Children's Day" was called "Tango no Sekku" and was a celebration for boys. But now it has become a day for all children. On this day, families decorate and eat special foods to pray for the happiness and healthy growth of their children.