Periscope is a collaboration between gta Archive and gta Exhibitions. It offers a window into the world of the gta Archive by periodically bringing into view materials usually preserved underground. The vitrine was designed by Rudolf and Esther Guyer for the Unterstrass vocational school for sales personnel in Zurich (1967–1973, now the vocational school for retail and pharmacy). Many other vitrines are still in use in the original building.