Where is the world’s oldest known surviving windmill?

Nashtifan, in northeastern Iran, is known for its ancient vertical-axis windmills, some of which date back centuries. These structures use strong local winds to grind grain and are among the oldest surviving wind-powered machines in the world. They are made from mud, clay, and wood, and their design differs from the more familiar European horizontal-axis windmills. Nashtifan is a striking example of early renewable technology adapted to a dry, windy environment.