PHOTO: IBERFOTO/THE IMAGE WORKS

Music was pervasive at the 1889 Exposition Universelle in Paris, but few of the sounds garnered as much attention as those emitted by the 25 phonographs in Thomas Edison's 7,226-square-foot exhibit. Thousands of attendees donned the devices' proto-earbuds to listen to "La Marseillaise" as well as voices speaking in 50 languages. Edison directed an assistant to record various European luminaries during the expo, resulting in the only known recording of a person born in the 18th century: the legendary German military strategist Helmuth von Moltke.