Roscón de Reyes.

King cake is said to have originated in Old World France and Spain and came to be associated with Epiphany during the Middle Ages.
Served in Spain and Latin America, it is a ring-shaped sweet bread that can also be topped with candied fruit, in addition to a light layer of icing. It marks Epiphany, the end of Christmas and the arrival of the three wise men/kings. It has to be said that it is delicious, and has already gone.

"Children in the English-speaking world often write a letter to Santa.   In the Spanish speaking world, it’s common for kids to write a note to the three magical kings.
 
Often on the eve of January 6th, kids tie a note to a helium filled balloon.
 
They let it go and watch it rise through the air up to the three wise men, which in this tradition are the three stars in the big dipper.
 
When they wake up in the morning, gifts appear in or next to their shoes.
 
Cultural differences like these are part of the magic in visiting or living in a Spanish speaking country."