im pretty sure it is the " GREAT WALL ".......
The Great Wall of China was built mainly to protect the Chinese Empire from northern invaders.
Shi Huangdi built the first incarnation of the Great Wall of China to protect China from invaders to the North.
to keep out the Mongol invaders
The Great Wall of China was built to protect the empire from northern invaders, particularly the Mongols and other nomadic tribes. Construction began as early as the 7th century BC, with significant contributions made during the Qin Dynasty (221-206 BC) and later during the Ming Dynasty (1368-1644). The wall served as a formidable barrier and a means of border control, military defense, and trade regulation. Its construction involved numerous workers, including soldiers, peasants, and prisoners.
Hadrian was an important leader because he built Hadrian's Wall which showed the northern limit of the empire. He also rebuilt the Pantheon and constructed the Temple of Venus and Roma. He is known to be one of the "Five Good Emperors." This may be because these emperors did not have biological heirs and were forced to pick an heir otherwise, meaning that they could pick someone good for the position instead of have an inept heir replace them.
To protect London from invaders.
It was built to protect the country from raids.
To stop the northern invaders.
To protect Chinese villages from Mongolian invaders.
It was built to protect China from Mongolian invaders.
aztec
Hadrian's Wall was built to protect the Roman province of Britannia, not Rome which was (and still is) about 1,140 miles from the area of this wall . not Rome. This province was part of the Roman Empire