Spain's coat of arms on its flag includes the Pillars of what?

Spain’s coat of arms on its flag includes the Pillars of Hercules.

The pillars are a heraldic reference to the Strait of Gibraltar, the narrow waterway separating southern Spain from North Africa. In classical geography, the strait marked the western edge of the known Mediterranean world, and the two rocky promontories at its entrance were associated with Hercules. They are commonly identified as Gibraltar on the European side and Jebel Musa in Morocco, although ancient traditions varied.

The pillars carry the Spanish motto “Plus Ultra,” meaning “further beyond.” The phrase reverses the older classical warning Nec Plus Ultra, or “nothing further beyond,” which supposedly marked the limit of navigation. Spain adopted Plus Ultra during the age of exploration to express the idea that its reach extended beyond the old imagined boundary.

A common mix-up is to treat the pillars as part of the central shield. Heraldically, they stand as supporters on either side of the shield, which represents historic Spanish kingdoms including Castile, León, Aragon, Navarre and Granada. The present national arms were established in 1981.