2. The Great Wall of China was built to protect China from its enemies and invaders from the North, especially the Mongols. Despite the wall, the Mongols eventually conquered China. It was built in the 5th–6th century during the Sāsānian dynasty and was designed to repel attacks, mainly from the Hephthalites and Turks. The Mongols were a tribal group that would regularly conduct raids into China. While little is known about the wall, the Parthians (247 BCE – 224 AD) who ruled Iran, are said to have built on the original remains of the wall. The great strength of the wall was not the wall itself, but the guardhouses built as part of the wall. That’s why Qin Empire built the Great Wall, fixing China’s northern border. The Bei Qi kingdom (550–577) built or repaired more than 900 miles of wall, and the short-lived but effective Sui Dynasty (581–618) repaired and extended the Great Wall … Another wall of this kind, still extant, is the Great Wall of Gorgan (known as `The Red Snake' due to the red color of the bricks) in modern-day Iran. The guardhouses have line-of-sight to each other and lots of ways to signal. 202 BC — The Great Wall Was Expanded to … This wall is known as ‘The Great Wall of Gorgan’ or ‘the Red Snake’. This Great Wall linked walls from today's Gansu Province to North Korea. It is of more solid construction than its ancient Chinese counterparts. The Great Wall of China is well known as the largest wall in Asia (or indeed the world). In total, the wall was 121 miles long. The Red Snake: The Great Wall of Gorgan . The structure is yet another testament to Sassanian engineering capabilities. A number of empires built “great walls” – the Roman Hadrian’s Wall, the Chola-Pandya Madukkarai Wall, the Sassanid Great Wall of Gorgan, the French Maginot Line, and, of course, the Great Wall of China. Less known is the Wall of Gorgan in northeastern Iran (specifically the plain of Gorgan) attributed to the Sassanian era (224-651 AD). The Great Wall of Gorgan. Less known is the Wall of Gorgan in northeastern Iran (specifically the plain of Gorgan) attributed to the Sassanian era (224-651 AD). It is the greatest monument of its kind between central Europe and China and it may be the longest brick, or stone, wall ever built in the ancient world – and yet few have ever heard of it. (Photo from Wikimedia Commons) The date of its construction is disputed. Why was the Great Wall of China bulit? The structure is yet another testament to Sassanian engineering capabilities. Some say it is 1,000 years older than the Great Wall of China. Situated in the city of Gorgan, the capital of northern Golestan province, the defensive wall is about 200 km in length and it was built to prevent the invasion of the northern tribes. It allowed soldiers to quickly run from where they were to where the enemy was, while the enemy was climbing rough terrain. To the east of the Great Wall is sea, and to the west is desert, and to the north were “ungovernable” tribes. The Great Wall of China is well known as the largest wall in Asia (or indeed the world). Great Wall of Gorgan Although not as well known as the Great Wall of China, this barrier in northern Iran lives up to its name.