Many millenniums a civilization so powerful and advanced once lived on these lands, they represented their faction with their brilliant architecture.
All their structures had the same architecture from defence towers to castles and citadels.
Endless souls have visited this place and stood in awe by the colossal scale of it, there is still no civilization on this planet that can achieve such immerse scale. Even by so millenniums have passed, the secrets haven't been discovered by many attempts by thousands of civilizations.
The structures haven't been ruined by a good reason, the material which is build of is extremely powerful, very durable and unsalvageable.
Also these lands are a very dangerous wastelands full of strong creatures that always have been many by the number and variation.
Its an excellent training ground for a veteran warrior looking for the greatest treasures that are hidden deep underground in these ancient places, ofcourse these structures provide perfect shelter for sandstorms/tornadoes. Most of the creatures are breeding in the structures.
In either way its a dangerous trade route, but extremely profitable. Traders that want to take an easy route will have to travel 8 times longer to the closest city with a great market.