Contrary to what Scooby Doo taught us, it's not always the owner of the factor/hotel/abandoned theme park who committed the crime.
These five mysteries remain unsolved, and many have produced myth upon rumour upon Illuminati levels of conspiracy theory.
We hope you enjoy them:
1. The Walrus was Pancras
The 'St Pancras Walrus' was discovered by archeologists excavating St Pancras Old Church in 2003.
The site had been used for mass graves, particularly due to a number of epidemics in the early nineteenth century.
According to List Verse, an estimated 44,000 bodies were buried there between 1822 and 1854.
One coffin contained the remains of eight humans, and a single Pacific walrus.
Extensive testing and study since then has failed to find an explanation for the walrus.
2. D.B Cooper
In 1971 a man known only as 'Dan B. Cooper' boarded a commercial Boeing 727-100 at Portland International Airport. The short flight, which took place on Thanksgiving, was bound for Seattle. Once in the air Cooper handed a flight attendendant a note. According to the attendant, the man explained to her that he had a bomb, and he wanted $200,000 USD and four parachutes.
The 30 minute flight was prolonged for over two hours to give the FBI time to assemble the ransom and parachutes.
The plane landed at Seattle-Tacoma Airport once Cooper's demands had been met, and he released all passengers and all but one of the flight attendants.
Cooper then ordered the cockpit crew to take off again and head to Mexico City. En route Cooper jumped out, never to be seen again.
3. Siberian sink holes
If you put 'Siberian' in front of anything it seems mysterious. So too for these sink holes.
In July 2015, a 115-foot hole appeared in the Yamal peninsular of Siberia. According to Mashable, 'Yamal' in the local indigenous language means 'end of the world'.
Despite sending a team into the sink hole in November 2015, the cause is still unknown.
Since the Yamal sink hole, two more opened up in the Taz district, and the Taymyr Peninsular.
Suggestions that it may have been a gas explosion, or permafrost sink holes, remain unproven.
4. Max Headroom, 11/22/1987
During a broadcast of a Tom Baker era episode of Doctor Who, the signal of a Chicago TV station was interrupted to show a sinister figure in a Max Headroom mask, barking unintelligble words.
The reason for this and the identity of the man in the mask remains unknown, although there have been a few theories.
The broadcast interruption lasted a little over 90 seconds. It's happening on 22nd of November has prompted some to connect it to the assassination of president John F Kennedy on the same day in 1963.
Earlier that day in 1987, the same figure, without sound, had interrupted a news programme on a sister station.
5. The loss of the original crown jewels
In 1216, during the First Baron's War, the Plantagenet King of England John was travelling from King's Lynn to Lincoln.
John and the royal train passed across the part of the fens known as 'The Wash' in the Sutton Bridge area.
During the journey his heavy treasure, including the royal crown, sunk into the mire.
The event was symbolic of John's position during the war with the Barons, after issuing the first and second Magna Carta documents.
Following John's death in the same year, his heir Henry III had to be crowned with a meagre 'golden circlet' at Gloucester Cathedral (Westminster being in the hands of the rebel barons).
Despite a search using lasers in 2015, these royal treasures have yet to be discovered.
As such, there is some speculation that John faked losing these treasures, and in fact had left them stored in King's Lynn.
His subsequent death weeks later made retrieving them impossible.