Poppenberg Observation Tower ( Poppenberg Observation Tower) is a steel German lattice observation tower that is used for observation, at the same time, for communication. It is a truss tower located in the summit of Poppenberg. It is one of the oldest steel lattice towers in Germany and was built in the year 1897. It was later on refurbished in 1994. The tower was built by the Nordhausen branch of the Harz Club. The tower was also named after Otto, Prince of Stolberg-Wernigerode. It has an antenna that is 33 metres long.