The 44 x 28 m "Monument to the Lost Falcon" can only be fully recognized from a bird's eye view. The New York artist Alan Sonfist has sculpted the silhouette of a hovering falcon from mounds of earth in a clearing in the Wittgenstein Forest. The mounds are reminiscent of the defensive mounds of Celtic fortifications in the immediate vicinity and have been planted with tree species that once dominated the forest in the region but have been displaced by humans. With the fencing following the silhouette, Sonfist symbolically protects his work from humans and animals, who often cause the originality of nature to be irretrievably lost through arbitrariness or browsing.