A large number of functionalities have been integrated into a single fully autonomous humanoid robot, HERMES. To evaluate the dependability of this extremely complex machine, and its ability to interact with strangers, HERMES was exhibited in a museum, far away from its home laboratory, for more than six months. During this period the robot and its skills were regularly demonstrated to the public by non-expert presenters up to 12 hours per day. Also, HERMES interacted with the visitors, chatted with them in English, French and German, answered questions and performed services as requested by them. Only three major failures occurred during the 6-month period, all of them caused by failures of commercially available modules that could easily be replaced. The key to this success was the dependability that had been originally designed into HERMES. During the design process certain design principles were followed in both hardware and software. These principles are introduced, and some long- and short-term experiments carried out with the real robot in real environments are presented. In fact, by demonstrating HERMES in the museum, at trade fairs and in TV studios — besides our institute environment — we have learned valuable lessons, especially regarding the interaction of a complex robotic assistant with unknown humans. Although we did not quantitatively evaluate the robot's performance or acceptance by the non-expert users, several qualitative results are given in this paper, and many videos highlighting these results can be downloaded from the HERMES homepage.