https://www.alamy.com/at-that-time-joseph-beuys-was-thought-to-be-insane-for-documenta-7-he-had-7000-oaks-planted-in-the-city-of-kassel-and-a-stone-block-next-to-it-today-kassel-is-greener-and-more-beautiful-eventually-because-of-this-documenta-project-by-joseph-beuys-kassel-germany-image364712154.html