This tour is blue and green. Bluestone, a particularly hard form of coal lime, was a valuable commodity in the Münsterland region and the wealth of Kornelimünster Abbey was based not least on this treasure. To this day, the hidden rock faces of former quarries, which can be found throughout the German-Belgian border of the Münsterländchen and Eupener Land, are reminders of the former extraction of limestone in the region. Bluestone has been used since Roman times for building houses and in arts and crafts due to its particular hardness. The name "Breiniger Marble" for the bluestone from the local quarry "auf dem Schomet" (1843-1970) speaks of pride and recognition.

To this day, the bluestone, which is actually rather grey-white in color, has shaped the face of many villages in the fringes of the quarries and has also spread its feelers to Aachen. In Kornelimünster, it was used in magnificent 17th/18th century town houses around the Korneliusmarkt. Over the course of the tour, it is farmhouses and churches that have turned Krauthausen, Dorff, Venwegen and Breinig into veritable blue stone villages.

We cycle through the hilly expanses of the Münsterland and before we cross the ups and downs in the secluded Münsterwald forest, we end up in Vichttal. The once water-powered Bernhardshammer still stands here today, a witness to the iron and later copper industry and other milestones in local industrial history. A favorable location for a mill, as the gradient at this point provides for correspondingly strong water power. The nearby limestone quarry was active until the 1970s and the stones were used in the cement industry. Today, like many others, it is a nature reserve.

Passing the outskirts of Venwegen, we reach the entrance to Breinig. A short detour to Alt-Breinig-Winterstraße and back is worthwhile. This is an entire listed street, whose bluestone houses have stood side by side since around 1600. In contrast to the stately Stockheider Hof, these are small farms with narrow plots for self-sufficiency. It is quite possible that the settlement was not built as a farming community but as a workers' settlement for those employed in the nearby quarries, lime kilns and ore mines.

Highlights along the route

• Historic center of Kornelimünster
• Historic center of Breinig
• Schlangenberg