Cambysey’s Army
In the year 525 BC, the Persian King Cambyses II is reputed to have led an army of 50,000 men into the Egyptian desert. According to the historian Herodotus, the army was sent from Thebes to the Temple of Amun's oracle to demolish it. They failed to succeed.
After a week, the army arrived at a desert oasis, but after they left, they vanished without a trace. According to Herodotus, a powerful wind caused the desert's sands to swallow the army entire. It has the feel of an episode of The Mummy. The ensuing puzzle had been a secret for ages.
It becomes out that Herodotus wasn't just making things up. Anyone who has lived in the desert knows that sandstorms are a genuine concern, and archaeologists have found proof that this is exactly what happened to the army.
Near a sizable rock, the kind of thing people might use to try to find cover in a storm, were human remains combined with tools and jewelry from the time Cambyrses would have dispatched his army. The burial with hundreds of bleached bones and skulls massed together was the most startling discovery. The army might have survived in large numbers, but even then, it would have been a dispersed and fragmented force.