The concept of the performance Podhoubí is based primarily on the environment, where it is performered - Gymnázium Jana Keplera high school in Prague. The ensemble is composed of high school students, and in combination with the siren sound it creates an unconventional performance, whose concept follows up on recent high-school student engagement regarding environmental issues (and related to recent public activity of high school student Greta Thunberg). Instead of explicit arguments, this performance uses improvised music, which is familiar to high school participants, along with sounds of natural objects, sound of siren, and free spoken improvization. The happening references to high school strikes related to current global environemntal crisis.