The Baghdad Battery is an ancient artifact discovered in the 1930s in the ruins of the city of Baghdad. It consists of a ceramic pot containing a copper cylinder and an iron rod. It is believed to have been used as a galvanic cell, possibly for electroplating gold onto silver objects
From Wikipedia
The Baghdad Battery or Parthian Battery are the names given to an artifact consisting of a ceramic pot, a tube of copper, and a rod of iron fixed together with bitumen. It was discovered in present-day Khujut Rabu, Iraq in 1936, close to the ancient city of Ctesiphon, the capital of the Parthian and Sasanian empires, and it is believed to date from either of these periods.