The main attraction of Bentheim is the castle dating back to the 11th century. Perched high on a sandstone cliff above the city, it now serves as the landmark and flagship of the city. It is considered one of the largest and most beautiful castle complexes in northwestern Germany. Five and a half meter thick sandstone walls protected the former residents of the castle from intruders. Even today, cannonballs from long past battles for the Bentheim Castle can be seen on the east side of the 30m high keep. If you continue following the route southward, you will reach the Sieringhoek. What few people know is that until the 19th century there was an asphaltite mine here, the shaft had a massive diameter of 4m and a depth of 127.5m. However, operations were discontinued in 1929. Since 2014, the once long-buried entrance to the mine, known as the Karl-Rudolf shaft, has been uncovered again and equipped with information signs.Note: Follow the signage in red!