The invention concerns a wind power installation comprising a rotor which is coupled to a generator within a machine housing. Such wind power installations have already long been known, for example the wind power installations of types E-40 and E-66 from Enercon, Aurich. The object of the invention is to improve sightseeing options of a wind power installation, in which respect more people than previously can view such wind power installations. A wind power installation comprising a rotor which is coupled to a generator within a machine housing, characterised in that an observation platform is arranged below the machine housing on the pylon of the wind power installation and is fixed by means of a support structure to the pylon of the wind power installation, wherein the support structure comprises an upper carrier arrangement and a lower carrier arrangement, wherein each carrier arrangement comprises a plurality of substantially identically formed support arms which are distributed around the periphery of the pylon, that the observation platform substantially completely surrounds the pylon, that the upper support arm arrangement carries a roof of the observation platform, that the lower support arm structure carries a floor of the observation platform, that the upper and the lower carrier arrangements receive holding means for windows which are distributed over the periphery of the observation platform and permit the user of the observation platform, in use of the observation platform, to have a panoramic view over the landscape.