Rai stones

Corybantian dance , the type of dance most likely danced on Gymnopedia festivals (image from Smith 's Dictionary of Antiquities ).

A thermite mixture using iron(III) oxide

Cosmic flux versus particle energy at the top of Earth's atmosphere

On Yap Island, a family's wealth included a 4-ton stone disc sitting on the ocean floor — sunk during transport centuries ago — yet everyone agreed they still owned it. The ledger was communal memory.