I was surprised to see Mario Merz's work at the MMK (Museum für Moderne Kunst) in Frankfurt. I first saw Merz's works last summer at Hallen für Neue Kunst in Schaffhausen and I was not allowed to take pictures.
Mario Merz' At The Still Point Of The Turning World at the MMK, Frankfurt 2012:
Douglas Gordon's August 12, 1999 at the MMK, Frankfurt 2012: