1. Amelia Earhart's disappearance In 1937, Amelia Earhart, a pioneer of aviation, disappeared over the Pacific Ocean while attempting to circumnavigate the globe. No one has been found to be locating her or her plane, despite multiple search attempts until now.

2. Jack the Ripper's  identity A group of gruesome murders committed by "Jack the Ripper" in London's Whitechapel neighbourhood in 1888 caused  a worldwide sensation.the murderer's true identity has never been determined with complete conviction, despite decades of police investigations and numerous theories.

3. The Mary Celeste's fate In 1872, the Mary Celeste, a vessel with all its supplies at sea, was discovered abandoned in the Atlantic Ocean. The crew's location is still uncertain.

4. The Loch Ness Monster The existence of a mysterious creature in Loch Ness, Scotland, has been documented for generations.The alleged "Nessie" has not been definitively proven despite numerous sightings and extensive investigations.

5. The Roanoke colony disappearance A group of English colonists settled on Roanoke Island, located off the coast of present-day North Carolina, in 1587. The colony vanished three years later on a supply ship, leaving only the mysterious "Croatoan" in ruins in one of the trees.

6. Voynich Manuscript The Voynich Manuscript is a peculiar, illustrated book that was written in an unknown language and script. Scholars and codebreakers have been puzzled by it for generations. The components and function of it remain a mystery.

7. The Zodiac Murderer During the late 1960s and early 1970s, the Zodiac, a serial killer, caused terror in northern California by amusing law enforcement officials and leaving behind secret messages. The killer's identity remains unknown despite numerous suspects being identified in subsequent investigations.