The meandering valley of the River Altmühl threads its way from west to east across the three-thousand-square-kilometre Naturpark Altmühltal, one of Germany’s largest nature reserves. Its Jurassic geology not only yields the remarkable fossils that are on display in the Willibaldsburg’s Jura Museum, but also produces fascinating, sculpted landforms, such as the Zwölf Apostel at Solnhofen west of Eichstätt. The region’s blend of scenic and cultural attractions makes it a popular destination for hikers and cyclists alike, and it is crisscrossed with hiking trails and cycle paths. The classic walk is the 200km Altmühltal Panoramaweg, which follows the course of the river, linking Gunzenhausen on the edge of the Altmühlsee in the west with Solnhofen, Eichstätt and Kelheim in the east. The gentle 166km Altmühltal Radweg for cyclists follows a similar route from Gunzenhausen to Kelheim. From May to October Freizeitbus services with bike trailers cover the region between Eichstätt and Regensburg; Freizeitbus #2 (day-ticket with bike €10.50; day-ticket without bike €7.50) follows the central sections of the Panoramaweg and Radweg. Altmühl itself is one of the slowest-flowing rivers in Bavaria and consequently highly popular with canoeists: Johann Gegg in Dollnstein west of Eichstätt rents out canoes by the day (from €17; 08422 691, boots-verleih.com). For more information on activities and accommodation in the Naturpark, contact the information centre in Eichstätt .