Dorper Höhlen

The Dorper Höhlen are a group of four or five small caves inside the old Dorp Tunnel, a 488-metre railway tunnel built between 1868 and 1872 on the abandoned Düsseldorf–Dortmund Süd line. The tunnel cuts through limestone layers known as the Dorp facies, making these the only caves of their kind in the area. Four separate cavities were mapped: the Dorper Laughöhle, Schachthöhle, Tunnelhöhle I and Tunnelhöhle II, with lengths from 16 to 45 metres and height differences up to 7.5 metres. In 2015 researchers recorded only four caves, suggesting that two smaller hollows may have been combined in the survey. Above the tunnel runs the Nüller Straße, a busy road that hides the hidden world below. These caves matter because they shelter rare bats. Water bats and greater mouse-eared bats spend the winter inside, while soprano pipistrelles and common pipistrelles hunt moths along the old railway bed on warm summer nights. The cavities were first studied in detail in 2008 by the Arbeitskreis Kluterthöhle, just before the tunnel was sealed off except for small bat entrances. The site is protected as a nature monument under North Rhine-Westphalia’s conservation law. Visitors walk the Northbahntrasse, a smooth path that follows the former railway line. The tunnel mouth appears as a dark arch framed by brickwork, but the interior is closed to people. From the path above, the hum of traffic on Nüller Straße mixes with the calls of bats echoing in the limestone. The surrounding Wuppertal hills provide a quiet green backdrop, while the tunnel itself remains a silent witness to the railway age and the bats that now call it home.