matza is the unleavened bread that is traditionally eaten during the jewish holiday of passover, which is from april 2nd through april 10th this year.
the story behind it is, when the jews had to leave egypt, they did not have enough time to cook the bread. so when they left, it had not had enough time to rise, and they eat it unleavened. it is now a tradition to eat matza during passover in remembrance of the exodus and what our ancestors had to go through.