They say that nothing is hidden forever. In fact, we find the answers to long-lasting questions seemingly regular. Even the truth behind the world's most lasting secrets might one day come to light.
It is impossible to predict when new developments will happen in ancient mysteries. A chance discovery here, a death bond there, and you have a hot new trail in a case that has been slumbering for decades. Sometimes you just need a fresh pair of eyes that can see things that everyone else misses.
10 The Claremont Serial Murders
For more than two decades, the Claremont serial murders were one of Australia's most terrifying secrets. The arrest of a suspect and the subsequent indictment with all three murders could bring it to an end in the coming months.
In 1996 and 1997, three young women disappeared into the Claremont suburb of Perth after drinking with friends. The remains of two of the victims were recovered weeks later, while the third is still missing and probably dead. The police were convinced that he was a serial killer and set up a task force to find him. Her biggest track was CCTV footage of a man on the night of her disappearance approaching one of the women, 23-year-old Jane Rimmer. This man, however, remains unrecognized.
The authorities have investigated several suspects without success, and for about 20 years it looked as if this mystery was destined for the "unsolved" pile. However, in 2016, police stormed 48-year-old Bradley Robert Edwards' home, a man with no prior (public) connection to the case. A day later, they accused him of killing the two women whose bodies had been recovered and two unrelated sexual assaults. In February 2018, he was charged by the police with the third murder, the missing person Sarah Spiers.  His trial will begin soon.
9 The Missing Sailor of the USS Indianapolis
Although it sank in 1945, the USS Indianapolis has been making some headlines lately. First, it was announced last year that an expedition led by Microsoft co-founder Paul Allen discovered the shipwreck after it was lost at sea during the Second World War. And last month, the US Navy admitted a mistake that had unsettled the number of survivors for over 70 years.
The USS Indianapolis was torpedoed by a Japanese submarine on its way to the Philippines. It sank in 12 minutes, and many sailors surviving the fall later succumbed to dehydration or shark attacks. Of 1,196 men aboard the ship, 880 died. That left 316 survivors, including Captain Quint of Jaws . However, other sources soon reported that 317 people survived the demise of the USS Indianapolis . There was a gap somewhere, and it was not revealed until recently.
This discrepancy was radio engineer Clarence Donnor. Although he was aboard the USS Indianapolis he immediately received word that he was to report to Fort Schuyler for officer training shortly before the ship abandoned its mission.  Due to a clerical error, his departure was not officially recorded. For this reason, the final crew list called 1,196 sailors instead of 1,195.
When it became known that Donnor was still alive, his name appeared on lists of survivors who said 317 people made it before Indianapolis . The navy, however, was firm at 316, though for some reason it never changed the list of seamen aboard the ship until March 2018.
8 The Brabant Killer Confession
The Brabant Killer represent one of the most violent and shocking chapters in the history of Belgium. Between 1982 and 1985, a gang committed a series of reckless attacks and robberies, mainly in the province of Brabant. There were 28 people killed and over 40 injured. The killers were never arrested and over the course of three decades many hypotheses and conspiracy theories were formulated regarding their possible motives. One of the most common beliefs is that the gang members came from law enforcement or the military because of their weapons skills.
In 2017, a man spoke up, saying his brother confessed on his deathbed in 2015 that he was the gang leader, a man formerly referred to as "the giant." This new suspect was Christiaan Bonkoffsky part of a police commando unit.  Bonkoffsky lost his position in 1981 after accidentally unloading his weapon and became very bitter, according to his brother, and started drinking heavily.
In the light of this recent development, the Belgian authorities have begun to investigate the former gendarmerie in the hope that this could lead to the identification of the other members of the gang. Bonkoffsky first appeared on his radar in 2000. However, his DNA sample and fingerprints did not match those of the crime scenes.
7 The Murder of Valerie Percy
In 1966, 21-year-old Valerie Percy was assassinated at her home in Kenilworth, a wealthy village north of Chicago. Her father was Charles Percy, a future senator who was in the middle of his election campaign. Her murder was never resolved and she became one of Chicagoland's most enduring mysteries.
While the killer remains unknown, new information has been made public because a New York lawyer has tried to open the file under the records. The Freedom of Information Act was rejected in 2016. His request was denied after a judge ruled on a statement and the Kenilworth police documents that the investigation had not been completed. The limited evidence proving the status of the case included several false confessions refuted by the use of confidential information and plans to use modern forensics such as DNA testing. 
A suspect was publicly named in 2014 a Chicago television station received access to FBI records. He was William Thoresen III, the son of a businessman who lived in Kenilworth. He was described as dangerous and mentally unstable. His family lived near the Percy household, and he often returned home to visit them. The police believed a bayonet was being used to kill Valerie and Thoresen was collecting weapons. The suspect refused to cooperate with the investigation and died a few years later. He was murdered by his wife, who had defeated herself with self-defense.
6 The Prime Minister's Death
Piotr Jaroszewicz was Prime Minister of Poland from 1970 to 1980. Jaroszewicz was expelled from the Polish United Workers' Party (PUWP) and gave up all policy. He retired with his wife Alicja Solska in a suburb of Warsaw. On September 3, 1992, her son Jan found the couple murdered in their home. Alicja had been shot in the head while her husband had been beaten and strangled.
The Polish police speculated that the murders were revenge on victims of the communist regime, the search for valuable documents, or an old-fashioned robbery. Despite the great national attention gathered by the murders, they could not find any solid clues.
In the year 2018 came the surprising announcement that three men had been charged with the murder. Not only that, but according to the Polish Minister of Justice Zbigniew Ziobro, two of them had already played their role in the killings.  The breakthrough came in the case when one of the killers revealed his involvement while he was being investigated for an act of separate kidnapping. He and the other two were part of a burglary ring aimed at high-income houses, so Jaroszewicz's killing does not seem to have anything to do with politics.
5 The Old Hell Gate
Archeologists discovered plutonium (also called Ploutonion) over 50 years ago in the ruins of Hierapolis, in what is now Turkey. Not just another shrine dedicated to Pluto, this place was built on a cave that was considered an actual passage into the underworld.
Ancient historians described the miraculous process of sacrificing healthy animals as victims. According to Strabo, every creature that was sent into the cave soon fell dead after it breathed a deadly fog that came from hell. Miraculously, the priests seemed untouched.
A team of volcanologists was able to provide a scientific explanation for the mysterious Gates of Hell. As you'd expect, there was a lethal gas that leaked from somewhere – especially huge concentrations of carbon dioxide that came from a gap below the ground.  Scientists measured CO 2 values between four and 53 percent at the mouth of the cave and up to 91 percent inside.
As for the seemingly immunized priests, the Greek philosopher, even in Strabo's time, believed that it was possible that the holy servants would simply hold their breath. Modern scientists, however, believe that the height of the priest has played a role. Since CO 2 is heavier than air, it settles on the ground and forms a poisonous alley. While animals inhaled carbon dioxide, the larger humans were relatively safe over the toxic cloud.
4 Did DeSalvo do it?
For many people, Albert DeSalvo was without a doubt the Boston Strangler. Others, however, have serious concerns and still see the case as unresolved. DeSalvo claimed responsibility for 11 killings between 1962 and 1964, but was convicted of a series of unrelated rapes and sentenced to life imprisonment. Finally, he revoked his own murder in 1973.
Since then, people have questioned his guilt. A popular hypothesis, supported by pioneering profilers Robert Ressler and John Douglas, claimed that there were more than one killer due to the different patterns between murders. Some groups, including the DeSalvo family, considered the former military completely innocent.
Modern forensics can at least refute this last thought. DNA testing conducted in 2013 linked DeSalvo to Mary Sullivan, Strangler's last known victim. After getting a sample from a suspected killer nephew, authorities could get a "family match" when comparing it to semen left at Sullivan Crime Scene. On the basis of this evidence, the officials obtained an exhumation order and tested DeSalvo's remains. The probability that the DNA belonged to another man was one in 220 billion.  Massachusetts Attorney Martha Coakley said there was "no doubt" that DeSalvo killed Mary Sullivan and was "most likely" the Boston Strangler.
3 The Black Dahlia Revisited
Is the notorious murder of Black Dahlia finally solved? Probably not, but a recent book claims to have uncovered the truth and once again spotlight the 70-year-long murder of Elizabeth Short.
British author Piu Eatwell identified Leslie Dillon as the culprit. Dillon was a former undertaker who could have given him the knowledge to drain and mutilate his body. He worked as a bellhop and could have committed the murder at the behest of Mark Hansen, a businessman from Hollywood obsessed with Short.
Dillon appeared on the LAPD radar as he tried to solicit information about the murder of the department psychiatrist. Joseph Paul De River. Under a pseudonym he claimed to write a book about psychopaths. After a few interviews, De River thought there was something wrong with Dillon, who argued that an acquaintance named Jeff Connors was the killer. The psychiatrist believed that Connors was imaginary and an extension of Dillon's personality, although he later turned out to be real.
Eatwell found a supporter in Buz Williams, a retired police officer whose father (also a police officer) served in the Gangster Squad. the original team that investigated the Black Dahlia murder.  According to Williams, both his father and partner believed that Elizabeth Short was killed by the Dillon-Connors-Hansen trio, although they differed as to who did the act.
Prosecution documents indicate that Leslie Dillon was in San Francisco during the murder. However, the author claims that corruption within the LAPD is the reason why Dillon was never arrested and pointed to a cover-up.
2 The Legend of Dents Run Gold
There are many hidden treasures still waiting to be found. In the United States, civil war in particular has spawned many stories of buried gold, and the FBI may have discovered one of those caches.
Legend has it that just before the Battle of Gettysburg in 1863, the Union Army sent a cart full of gold to pay their soldiers. It went from Wheeling, West Virginia, but disappeared somewhere near Dents Run in Elk County, Pennsylvania. Since then, many treasure hunters, historians and private investigators have sought out these forests in the hope of finding the lost gold, all in vain.
In March 2018, the FBI set up a shop near Benezette Township and began digging. They were given a court order to do so, which led to speculation that they needed convincing evidence that the gold was there.
The FBI provided few details about their intentions. Spokeswoman Carrie Adamowski said simply that she was carrying out an excavation and concluded that "nothing was found".  Local media reported that Dennis and Kem Parada were present at the site. The two run a treasure recovery service called Finders Keepers and have been searching for decades for the spoils of the Civil War. Other local historians are much more skeptical about the existence of gold, but even they agree that the FBI's involvement adds a new layer to the mystery.
1 Toronto's Gay Village Murders
One of the most shocking stories that came this year from Canada was the arrest of Bruce McArthur and subsequent allegations that he was a serial killer. In January, he was initially charged with two murders, others followed him. A few days ago, McArthur received his seventh first-degree murder charge.
All alleged victims were killed between 2010 and 2017, but the authorities are fairly confident that McArthur had already started his crime dream. The 66-year-old works as a landscape gardener and has buried remains in large flower tubs he has installed in and around Toronto. The Canadian authorities are planning to search over 75 more properties and search for more victims. Senior investigator Detective Sergeant Hank Idsinga said that she is currently being investigated in 15 colds between 1975 and 1997.
Among these cases, one of Toronto's most infamous killing sprees could be: the gay village murders of the 1970s. Between 1975 and 1978, 14 men were killed from the gay scene of the city. Many of these killings took place in the church and at Wellesley Village and showed signs of overkill. A disco manager was found in his home after being stabbed 100 times. Seven of these murders are still unresolved.
It would not be too far-fetched to consider McArthur a culprit. He was in his mid-twenties and worked in Toronto.  Some of the victims were last seen leaving bars, reflecting McArthur's modern modus operandi. He would pick men up either in bars or dating apps. Idsinga emphasized that the landscape gardener was not associated with any of these murders, but he would not be surprised if they found ties to one or more of the murders down the line.