In the territory of the Polytechnic Park, among the autumn trees, there is a structure that can easily be mistaken for the tower of an ancient castle. An octagonal stone base, narrow windows, a wooden panel and a pointed tower - it seems that in one of the windows a little more will appear, and a princess from the fairy tales. But there is no legend. Or rather, not really. It is a hydraulic tower built in 1905 (height - 46 meters). It was not created for the sake of beauty: the tower supplied water to the institute and served in this role for almost half a century - until 1953. And during the siege of Leningrad there was an air defense observation post here. The building, which today looks like a setting for an old fairy tale, was from the beginning part of real engineering history. Here they studied, conducted tests and developed science. And now you can go up and see Petersburg completely differently - with roofs, autumn crowns and an endless sky. Quantum man.