Five monks witnessed something extraordinary on June 18, 1178, an event recorded by Gervasi of Canterbury that defies easy explanation. The moon's upper horn split in two, and from that division came what they described as fire, hot coals, and sparks. The body of the moon below writhed and throbbed like a wounded snake. This wasn't folklore or legend passed down through generations. This was a direct eyewitness account, translated from Latin, describing a celestial phenomenon that modern science has tried to reconcile ever since. What could cause the moon to appear as though it were splitting and ejecting material? Some researchers have proposed an impact event on the lunar surface, potentially forming the crater Giordano Bruno. Others remain skeptical of that interpretation. What's undeniable is that something happened that night, something dramatic enough to be recorded with precision and preserved for nearly a millennium.