If you haven't heard of Polybius, here's the short version: In the fall of 1981, a mysterious video game suddenly appeared in arcades around Portland, Oregon. The game—a black box with no name that involved geometric patterns and colorful shapes—was instantly addictive, hypnotic, and, in some cases, dangerous. Two teenagers supposedly disappeared after playing it. Mysterious men in black suits periodically came to service it. Some people think that it was a secret government research program using gamers as unwitting guinea pigs. Others think that it may have been part of the CIA's MK-Ultra (incredibly illegal) mind control program. Have you ever played a video game at an arcade?

There is an area in Beaver Dunes Park, Oklahoma that is known locally as the "Shaman's Portal." Many call this park Oklahoma's Bermuda Triangle. Several people have reportedly disappeared into this portal. The theory? Legend has it that the area is a UFO crash site, and all the people that had made reports about it can no longer be found or contacted - as in "disappeared". Do you think that portals to other dimensions actually exist?

Urban legend says there's a "portal to hell" in Blue Ash, Ohio. A group of Satanists supposedly used to meet there in some type of altar room where they would conduct their rituals. They must have been pretty good, because the legend claims they managed to open a doorway to hell. Dubbed "Satan's Hollow" by area residents, it's located in the woods, near a storm drain — and it's on private property. Many residents claim to hear screams from the tunnel at night, and others report seeing floating images. Have you ever seen/heard something that you just couldn't explain?

If you've seen Stranger Things on Netflix, a lot of this is going to sound familiar, because Montauk, New York, was the inspiration for Stranger Things, according to some people. Montauk is a long-time center of weirdness. Its old military base, Camp Hero, is said to have been the site of top-secret, black-book experiments in the 1960's and through the 1980's that involved alien contact, psychic experiments with children, and even time travel. Did you know that according to Albert Einstein's theory of relativity, time travel to the future is theoretically possible, as traveling at speeds close to the speed of light would cause time to slow down for the traveler relative to a stationary observer, essentially allowing them to experience the future at a faster rate? However, traveling back in time is considered highly unlikely based on our current understanding of physics. Would you like to be able to travel through time?