Seven sleepers in a cave - seven time travelers? 

One of the first authentic reports of time travel has no real explanation yet, and remains a mystery. The story proves that ancient civilizations may have had knowledge of time travel. 

Unexplained case of seven sleepers

The story goes that during the persecution of Deci (250), when Christianity was in conflict with the Roman Empire, seven young men entered a cave one night, where they all fell asleep after a while. The next day they woke up and went to the city of Ephes to buy food and drink. However, when they arrived in Ephesus, they were amazed to find that time had passed very quickly! They did not sleep one night, but for two hundred years. At that time, Christianity spread to all corners of the Roman Empire. When Emperor Theodosius II heard about the case, he accepted it as evidence of the resurrection and declared that the seven sleepers had in fact been dead for two hundred years. When the Sleeper later died, they were buried in a cave where they once slept.

The Seven Sleepers' Cave is located on the eastern slope of Mount Panayirdah in Turkey.