"The sky in the Brohl valley darkened when the Laacher See volcano erupted just five kilometers away. A scorching mixture of lava particles and gases shot into the atmosphere at intervals. Every time the eruptive column collapsed, the material rushed up an air cushion through the surrounding valleys - ash and lava particles filled the valleys up to 60 meters high. Over time, the loose materials of the glowing avalanche have caked into a rock that is known in our region as “Trass”. The Romans built it In the Brohl Valley Trass and used it for building houses, among other things. Finely ground it with the addition of lime and water results in a mortar that hardens under water. It is obvious that it was the Dutch who began mining in the Brohl Valley in the 16th century because Trass is ideal for the construction of dykes and docks, and it was you who gave the volcanic cement its name: “Tyrass” is Dutch and means “glue” Trass walls, which you can see from here, have been excavated and can be visited. Because of their poor quality, they were no longer of interest for mining and are now an impressive testimony to the huge glowing avalanche that once filled the entire valley. "
October 14, 2019
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