The Heinrich-Hertz-Turm (named after the German physicist and Hamburg-born Heinrich Hertz) is a radio telecommunication tower and a famous landmark of Hamburg, Germany. Designed by architect Fritz Trautwein, in co-operation with civil engineers Jörg Schlaich, Rudolf Bergermann and Fritz Leonhardt, it was built 1965–1968 for former Deutsche Bundespost (German Federal Post and Telecommunications Agency, now Deutsche Telekom's subsidiary Deutsche Funkturm GmbH) near Planten un Blomen (a city park). With an overall height of 279,2 m (916 ft) it is Hamburg's tallest building; it comprises a 204 m (670 ft) steel-enforced concrete lower section, topped by a 45 m (148 ft) steel-lattice tower and a three-segmented cylinder of about 30 m (98 ft), which supports various antennas. There are eight concentric platforms stacked one above the other; starting at 128 m (420 ft) with the two-story observation (lower floor) and restaurant (upper floor) platform, served by two high-speed elevators. Above that at 150 m (492 ft) is the operations platform housing the workforce and equipment, and further up six differentially sized, smaller open platforms in same distances, populated with high-gain directional microwave radio relay antennas ("parabolic mirrors"). Number nine was added at 25 m height in July 2005. After the observation platform and restaurant were closed (due to asbestos decontamination), former stuntman Jochen Schweitzer had a bungee jumping base installed. The restaurant will not open again due to new fire escape regulations, the bungee platform was closed at the end of 2001. The tower has been home to the VFDB Hamburg section's radio amateur club station "DF0HHT". It also housed a DGPS transmitting station serving the city of Hamburg's Surveying Agency. A memorial plaque on the tower's wall reads: " Heinrich Hertz – Dem Sohn der Stadt Hamburg" honouring the city's famous son.