In this Paper we present a continuously extendable and retractable tower construction: The Helix-Tower by Konrad Zuse. From 1989 onwards Zuse worked on the design of the heightadjustable tower. In 1993 Zuse had accomplished the prototype HT1 on a 1:30 scale to test the construction. In 1992 he started sketching up a second model (HT2) on a 1:10 scale, which was planned to be the forerunner of an initial experimentary tower on full scale. The prototype can be extended to a height of 270 cm; the full-scale tower had been schemed to reach 120 m. The analysis of archival documents and reports by witnesses revealed that Zuse intended his tower to be used for wind power installations, for observation and for radio transmission. The prototype of the Helix-Tower, and therefore the only existing model to experience the function of the HT, together with his estate has been at the Deutsche Museum in Munich since 2006.