Read more about the three kings - Melchor, Gaspar and Baltasar and the Spanish Christmas traditions.
The best-loved Spanish Christmas tradition among kids is Los Tres Reyes Magos (the Three Wise Men). Santa Claus is quite well-known as he delivers toys and presents, but the real stars in Spain are los Reyes. These Three Kings are the ones who followed a star to meet the new King of Kings (Baby Jesus) and offered him three presents: gold, frankincense and myrrh to the newborn child in Belén (Bethelem).
When December comes, all the boys and girls in Spain and Latin America start to write their letters to the Three Kings or to their favorite King: Melchor, Gaspar or Baltasar. They write about the things they'd like to receive on the morning of the 6th of January, (which is the day the presents get delivered) and also about their behavior during the year. If they've been good, they get presents; if they've been bad, they get a piece of coal.
Their Majesties travel by camel and due to the fact that they come from the East, they take a long time to arrive to Spain. Once here, they visit all the cities and villages, and listen to the kids' requests, after a spectacular parade. On the night of the 5th, the kids put their shoes by the door before going to bed so that the Kings will know how many children live there. They also put out something to eat and drink for Melchor, Gaspar, and Baltasar, and also water and grass for the camels (true, they can last a month or more without drinking water, but that night they have a lot of work to do, so they need extra water and food).
On the morning of the 6th, children find their presents inside and outside the shoes (it's very unusual for their Majesties to bring carbones (coal) because no child really behaves so badly, and many people say it's not true that naughty girls and boys get only coal and no toys). The food and drink placed in the plates and glasses are gone. The children start playing with their toys, and excitedly wait for the next 5th of January to come around.