three horizontal bands of red (top), yellow (double width), and red with the national coat of arms on the hoist side of the yellow band
the coat of arms is quartered to display the emblems of the traditional kingdoms of Spain (clockwise from upper left, Castile, Leon, Navarre, and Aragon) while Granada is represented by the stylized pomegranate at the bottom of the shield
the arms are framed by two columns representing the Pillars of Hercules, which are the two promontories (Gibraltar and Ceuta) on either side of the eastern end of the Strait of Gibraltar
the red scroll across the two columns bears the imperial motto of "Plus Ultra" (further beyond) referring to Spanish lands beyond Europe
the triband arrangement with the center stripe twice the width of the outer dates to the 18th century
note: the red and yellow colors are related to those of the oldest Spanish kingdoms: Aragon, Castile, Leon, and Navarre