Students and teachers across Colorado have been encountering strange symbols at their universities.
Law enforcement agencies have been left baffled by a spate of unexplained explosions in Fair Lawn.
A new mystery has arisen in the area where nine hikers died under mysterious circumstances back in 1959.
Scientists have finally discovered the spot where Apollo 16's S-IVB rocket stage impacted on the moon.
A high-profile mass UFO sighting in Australia is still no closer to being solved after five decades.
A beach in Cornwall has been deluged by thousands of bright neon pink bottles over the last few days.
Scientists have finally determined what the dwarf planet's mysterious bright spots actually are.
Today marks the 50th anniversary of the UFO which streaked across the US and crashed near Kecksburg.
It's been over seven decades since the first aircraft disappeared while flying over the enigmatic region.
A mysterious humming noise that has been driving residents round the bend may be coming from the sea.
The man who successfully hijacked an airliner in 1971 might have been a missing grocery store manager.
Scientists have been struggling to explain why some UK garden birds are drowning themselves en masse.
Mystery surrounds the deaths of several hundred fish found along the shoreline to the south of Perth.
Archaeologists have long struggled to explain the nature and origins of the ancient Steppe Geoglyphs.
Residents of a remote island community have been plagued by mysterious screams and howling noises.
Newly declassified documents suggest that authorities knew all about the Broad Haven Triangle mystery.
Dashcam footage has revealed the moment a fireball lit up the sky over Thailand on Monday morning.
A perplexing series of unexplained phenomena hit the English town of Warminster back in the 1960s.
Efforts to uncover the secrets of the tomb linked to Alexander the Great in Greece have come to a halt.
Researchers have identified a subtle optical illusion responsible for the painting's enigmatic smile.