Autoren Galerie Kostka

Kostka applied his architectural concept "Gewinnung von Räumen" (Reclaiming Spaces) to the tower, as he also did at the Uevekoven water tower. He stripped out all technical fittings, cut four door-sized openings into the tank walls, and painted everything white, creating a labyrinth-like structure built on the principle of "space within space." Inside, the original open-topped water reservoir, measuring 3.0 × 3.7 × 3.8 meters, was preserved. Two rows of three windows each face one another beneath the outer chamber's ceiling, and an intermediate gallery of steel grating let visitors view the space from every angle. It opened to the public on 6 December 1992.

Once the "space within space" concept was complete, the tower became a permanent exhibition venue. Referencing his Polish roots, Kostka named it Autoren Galerie — an artist-run gallery in the tradition of producer galleries. Invited artists used the interior as a performance space, offering visitors ever-changing spatial experiences; architectural photographer Tomas Riehle opened the series.

Over its eight years, the gallery presented numerous internationally noted exhibitions, with contributors including Frances Scholz, Daniel Tschannen, Enno Stahl, Volker Saul, A. Harold Barreiro, Katrin Nalop, and Hongku Kwon. In 1995 and 1997 the tower served as a venue for the Internationale Photoszene Köln, held alongside Photokina. Notable installations included Seyed Mohammad Oreyzi's "Zeitraum" (1992/93), made of ice blocks, iron crosses, and neon light, and "Really Virtual Reality" (1995), in which Kostka linked the tower via photo and video transmission to a former coal bunker, juxtaposing "space within space" with "space without floor."