Great Wall of Ottolan

The Great Wall of Ottolan was constructed by the Gattamir Empire at the wake of the Oil Wars to act as a major defense point and to protect the Ottolan Oil Fields against the Quantonian Empire. The wall itself is made of a cheap form of concrete using desert sand, water, mud and ash, these materials were used due to the fact the wall needed to be built quickly. The wall was built just in time before the Empire arrived but was soon breached by the Quantonian Empire due to them using high explosives against it.
The wall still stands today but in ruins from the battles of that war