See if you can figure this one out:
#2 The Baghdad Batteries
The Baghdad Batteries are a series of artifacts found in the area of Mesopotamia dating from the early centuries AD. This was the approximate time when Gozer the Gozarian was roaming the lands, morphing into whatever you thought of and then devouring you [source].
When archaeologists stumbled upon the batteries, they assumed they were just regular old clay pots for storage, but that theory quickly went out the window since they each contain a copper rod that shows evidence of acid corrosion. Now, in case you weren't the biggest nerd in school, this means that the pots probably contained a liquid that would interact with the copper and produce an electrical charge. If true, they predate the first known modern battery by hundreds of years.