The castle is for Castile. The lion is for Leon. The stripes are for Aragon. The chains in the shield are for Navarre. The little pomegranate represents Granada. The fleurs-de-lit in the middle represent the House of Bourbon, the family of King Juan Carlos. The thing at the bottom represents the Order of the Golden Fleece, a chivalric order founded by one of the king's ancestors in the 1400s.