Hidden beneath the serene landscape of Col des Roches lies a testament to human ingenuity: the extraordinary underground mills. These remarkable structures, established in the 17th century, represent a unique fusion of natural geology and mechanical prowess, where the powerful flow of the Bied River was harnessed to drive an intricate system of mills deep within the earth's karst formations. This historical site invites visitors to journey through its subterranean passages, offering a glimpse into an industrial past that adapted to and utilized its unique environment.

Exploring the complex reveals a captivating narrative of innovation and adaptation. Guests can descend into the depths, observing the colossal waterwheel in action and tracing the path of the river through three distinct levels, culminating in the location of a former sawmill. Each turn unveils more of this underground marvel, with multilingual audio commentary enriching the experience by detailing the site's rich history, from its foundational purpose to its surprising later use as an unlikely waste management facility for a local abattoir. Adjacent to the mills, a dedicated museum further expands on the regional heritage through both permanent and rotating exhibits, providing a comprehensive understanding of the area's historical development.

The ingenuity displayed at the Col des Roches underground mills underscores humanity's enduring capacity for problem-solving and transformation. It reminds us that progress often involves looking beyond the obvious, embracing challenges, and discovering innovative solutions within existing resources. This site, a blend of natural wonder and historical industry, stands as a symbol of how human endeavor can harmoniously interact with and repurpose the environment, leaving behind a legacy that continues to inspire and educate.