No. 55: Jan-Feb 1988
"Scientists who found a curved piece of mammoth tusk in a cave in southern Poland have dubbed it the world's oldest known boomerang, dating to about 23,000 years ago.
"The claim is based on the artifact's shape: its curvature and flattening at both ends, report P. Valde-Nowak and his colleagues of the Polish Academy of Sciences in Krakow. It spans about 27 inches and is up to 2.3 inches wide and 0.6 inches thick. One side preserves the external, rounded surface of the tusk, while the other has been polished almost flat."
(Bower, B.; "Prehistoric Tusk: Early Boomerang?" Science News, 132:215, 1987.)