On November 8, 1895, physicist Wilhelm Conrad Röntgen 
(1845-1923) became the first person to observe X-rays, a
significant scientific advancement that would ultimately
benefit a variety of fields, most of all medicine, by making
the invisible visible.

Röntgen’s discovery occurred accidentally in his Wurzburg,
Germany, lab, where he was testing whether cathode rays
could pass through glass when he noticed a glow coming
from a nearby chemically coated screen. He dubbed the rays
that caused this glow X-rays because of their unknown nature.