Once considered the "Eighth Wonder of the World," the Amber Room was a dazzling chamber made entirely of amber panels, gold leaf, and mirrors. Created for Prussia's Frederick I and later gifted to Russian Tsar Peter the Great, this masterpiece was looted by Nazi forces during WWII and transported to Königsberg Castle. Then it simply vanished.

Some believe it was destroyed during Allied bombing raids, while others insist it was secretly disassembled and hidden in abandoned mines or bunkers across Eastern Europe. Despite numerous expeditions and a $10 million reward offered by the German government, this breathtaking treasure remains missing – though amber fragments occasionally surface, rekindling hope of finally solving this 80-year-old mystery.

When it disappeared in 1948, the Patiala Necklace was one of the most expensive pieces of jewelry ever created. Commissioned by Maharaja Bhupinder Singh of Patiala from Cartier in 1928, this extravagant necklace contained 2,930 diamonds and the world's seventh-largest diamond at the time – the 428-carat "De Beers." It mysteriously vanished from the royal treasury, leaving no clues behind. 

Decades later, parts of the necklace turned up at a London auction house in 1982, minus all its major diamonds. Cartier purchased these remnants and restored the piece with replica stones. But the original massive diamonds remain missing, presumably recut and sold on the black market. Jewelry historians haven't given up hope that the De Beers diamond might someday resurface, still recognizable despite alterations.

The 1907 theft of the Irish Crown Jewels remains one of the most baffling unsolved crimes in British history. The jewels – including the heavily decorated Star and Badge of the Order of St. Patrick, studded with Brazilian diamonds – were stolen from a safe in Dublin Castle just days before a royal visit. What makes this case so strange is that only a handful of people had keys to the tower where they were kept. Scotland Yard questioned several suspects but never made an arrest. 

Rumors swirled about an inside job, drunken pranks gone wrong, and even blackmail involving homosexual scandals. The jewels, worth about $20 million today, have never resurfaced in any market. Many Irish treasure hunters believe they may still be hidden somewhere in Dublin, waiting to be uncovered during renovation of an old building.

Related: These Captivating Treasures Were Lifted From Shipwrecks! 

Of the 50 Imperial Fabergé Eggs created for the Russian royal family, eight remain missing following the chaos of the 1917 Revolution. Each egg was a masterpiece containing spectacular surprises inside – from miniature carriages to working clocks. 

Their disappearance seemed permanent until 2014, when a scrap metal dealer purchased one at a market for $14,000, planning to melt it down for gold. Before doing so, he googled "egg" and "Vacheron Constantin" (inscribed on the timepiece inside) and discovered its true value: $33 million. This shocking rediscovery has fueled speculation that the other seven eggs didn't perish in the revolution but instead sit unrecognized in attics or private collections. Experts estimate that finding any of these eggs would be like winning the lottery – they're valued between $30-60 million each.

The Royal Casket, a 16th-century treasure chest that belonged to Poland's Queen Bona Sforza, disappeared under bizarre circumstances. The ornate ebony box, inlaid with silver decorations, contained the queen's most precious documents and jewels. When Bona fled Poland for Italy in 1556, she took the casket with her, but she died shortly after arrival – possibly poisoned. 

Spanish authorities seized the casket, and it eventually ended up in the Simancas Castle archive near Valladolid. During Napoleon's invasion in 1810, a French officer reportedly took it. The chest changed hands multiple times before vanishing completely during World War II. Polish researchers tracked it to an art dealer in Spain in the 1920s, but the trail goes cold after that. Urban legends insist it's hidden in a private collection in South America, its owner unaware of its historical importance.

In 1955, diver Teddy Tucker discovered an extraordinary gold cross adorned with seven emeralds near Bermuda. This 22-karat gold masterpiece, dating back to the 1594 San Pedro shipwreck, became the pride of Bermuda's maritime museum. However, during preparation for a royal visit in 1975, curators made a shocking discovery – the cross on display was a plastic replica! 

Someone had broken in and switched it without anyone noticing. Despite an international investigation by Interpol and the FBI, the priceless artifact never resurfaced. Most experts believe the cross was melted down long ago, but a few treasure hunters remain convinced it was sold intact to a private collector in the Middle East. Every few years, rumors circulate about the cross appearing in underground auctions, only to slip away again into obscurity.

The 137-carat yellow Florentine Diamond counts among history's most notorious missing gems. First owned by the Medici family in the 16th century, it later became part of the Habsburg crown jewels in Austria. After the collapse of the Austrian-Hungarian Empire in 1918, the imperial family fled with their treasures, including this remarkable nine-sided diamond. The stone disappeared during their escape, triggering endless speculation. 

Some evidence suggests the diamond made its way to South America with the exiled Habsburg family, who may have had it recut to disguise its identity before selling it. Others claim it was stolen from Emperor Charles I's luggage. Diamond experts regularly examine large yellow diamonds that appear on the market, hoping to identify cut patterns that might reveal the recut Florentine. 

The diamond's unique yellow color and exceptional clarity would make it nearly impossible to hide completely, keeping hope alive that it would eventually reappear.

The Peking Man fossils represent one of paleontology's greatest mysteries. Discovered in the 1920s and 30s near Beijing, these 500,000-year-old Homo erectus remains were groundbreaking evidence of human evolution. As Japanese forces approached Beijing during WWII, American scientists packed the irreplaceable fossils into wooden crates for shipment to the United States for safekeeping. The fossils were last seen being loaded onto a train headed for a port city, but they never reached their destination. 

Numerous theories exist: they might have been buried by frightened guards, stolen by looters, lost in a shipwreck, or even destroyed during wartime chaos. Chinese authorities still actively search for these missing links in human history, and rumors occasionally emerge about the fossils being hidden in someone's basement or forgotten in an unmarked crate in a museum storage room somewhere in America.

Admiral Horatio Nelson's Chelengk, a diamond-studded turban ornament, might be the most unusual missing treasure from British history. The Ottoman Sultan gifted this spectacular jewel to Nelson after his victory at the Battle of the Nile in 1798. Featuring 13 diamond rays that could be set in motion by a clockwork mechanism, Nelson wore this "springing star" proudly on his hat for the rest of his life. 

After passing through generations of his family, the Chelengk was stolen in 1951 from London's National Maritime Museum by a daring cat burglar who scaled walls and broke through a skylight. 

Authorities suspect it was dismantled for its diamonds, but others believe the thief sold it intact to a private collector obsessed with Napoleonic memorabilia. In 2018, a perfect replica was created based on surviving drawings, but the whereabouts of the original remains one of Britain's greatest unsolved art crimes.

On June 30, 1520, Hernán Cortés and his men fled Tenochtitlán under cover of darkness, loaded down with Aztec gold and treasures. Many Spanish soldiers, weighed down by their plunder, drowned while crossing Lake Texcoco during this "Night of Sorrows" (La Noche Triste). Historians believe that massive amounts of looted Aztec treasure sank to the bottom of the lake that night.

Modern Mexico City now stands where much of Lake Texcoco once was, making traditional recovery methods impossible. However, archaeological projects occasionally uncover Aztec artifacts during construction work in specific areas of the city. Ground-penetrating radar technology has identified several anomalies beneath the urban landscape that could represent caches of the lost treasure. Every new skyscraper foundation dug in Mexico City brings fresh hope of stumbling upon Cortés' abandoned plunder.

The Great Bell of Dhammazedi was the largest bell ever made - weighing 300 tons and containing massive amounts of gold, silver, and other precious metals. King Dhammazedi of Burma donated this monumental bell to the Shwedagon Pagoda in the late 15th century. In 1608, Portuguese warlord Filipe de Brito decided to steal it, planning to melt it down for cannons. His men rolled the bell down a hill and loaded it onto a raft to cross the Bago River. 

Predictably, the immense weight sank the raft at the junction of the Bago and Yangon rivers. For over 400 years, the bell has remained somewhere in the riverbed mud, with its exact location lost to time. Countless expeditions have tried to locate it using modern technology, but silt deposits, dangerous currents, and poor visibility continue to complicate recovery efforts. Myanmar considers finding the bell a matter of national pride, with new search attempts launched almost every decade.

Related: The US Is Home to 6 Extremely Valuable Hidden Treasures

When the luxury liner RMS Republic sank in 1909 after a collision off Nantucket, rumors spread that it carried a fortune in gold coins – possibly $3 million (worth over $1 billion today). Some historical records suggest this treasure was a loan from the U.S. government to Russia, while others claim it was relief money for survivors of a massive Italian earthquake. Salvage attempts began almost immediately after the sinking but yielded nothing significant. 

The ship lies in relatively shallow water (270 feet), yet its cargo holds have proven remarkably difficult to access due to the vessel's deterioration. Treasure hunter Martin Bayerle spent decades researching the Republic and finally secured exclusive salvage rights in the 1980s. The gold has eluded several expeditions, including one captured on the History Channel. Bayerle remains convinced it's still there, hidden beneath collapsed decking or buried in sediment, waiting for the right technology to reveal its hiding place.

In 1820, as Spanish rule in Peru collapsed during the wars of independence, authorities in Lima decided to evacuate their vast wealth to Mexico for safekeeping. They loaded an estimated $60 million in gold, jewels, and church artifacts onto the British trader Mary Dear. The ship's captain, William Thompson, proved untrustworthy – he killed the Spanish guards and sailed to Cocos Island off Costa Rica, where he allegedly buried the entire treasure. Later captured, Thompson agreed to lead authorities to the hoard but escaped into the jungle. 

Since then, over 300 expeditions have searched the tiny island, turning much of it into a honeycomb of pits and tunnels. The Costa Rican government has since banned treasure hunting there to protect the ecosystem. Some researchers believe the treasure never reached Cocos Island at all but was instead divided among the crew and quietly sold off. Others remain convinced it's still buried somewhere on the island, protected by booby traps or hidden in underwater caves accessible only during certain tidal conditions.

The Scepter of Dagobert, created in the 7th century for the Merovingian king of the Franks, ranks among the oldest royal regalia in Europe. This gold ceremonial staff, topped with an intricate throne with a seated figure, disappeared during the French Revolution when revolutionaries raided the Royal Abbey of Saint-Denis. Unlike other royal treasures that were officially melted down, no records confirm the scepter's destruction. This administrative gap has led many historians to believe it was stolen rather than destroyed.

The scepter briefly appeared in Napoleon's time – mentioned in inventory documents but never displayed – before vanishing again. Art detectives have followed leads suggesting it was smuggled to England, then to Russia with aristocrats fleeing the revolution. Others believe it never left France but remains hidden in a provincial church or private chateau, its significance unknown to its current owners, who might mistake it for an ordinary church ornament.

The left panel of the famous Ghent Altarpiece, known as "The Just Judges," represents the most valuable stolen artwork never recovered. On April 10, 1934, thieves removed this panel from Saint Bavo Cathedral in Belgium, leaving a note that read, "Taken from Germany by the Treaty of Versailles." 

The suspected thief, Arsène Goedertier, revealed on his deathbed that he alone knew where the panel was hidden, but died before sharing its location. He left behind cryptic clues that investigators still haven't deciphered nearly 90 years later. The panel's oak backing was found in the thief's possession, suggesting the painted portion might be hidden separately. 

Countless searches have examined church crypts, wells, and abandoned buildings throughout Belgium. The panel currently on display is a remarkable reproduction created in 1945. Experts remain divided – some believe the original was destroyed long ago, while others think it remains hidden somewhere in Ghent, perhaps even within the cathedral itself.

Deep in Ecuador's Llanganatis Mountains lies what might be the largest undiscovered treasure in the Americas – the lost gold of Atahualpa, the last Inca emperor. When Spanish conquistadors captured Atahualpa in 1532, he offered a room filled with gold and two rooms of silver as ransom. 

While his people were delivering this fortune, news arrived that the Spanish had decided to execute the emperor anyway. The Inca messengers allegedly dumped the remaining gold – thousands of pounds of it – into a remote mountain lake or buried it in a hastily-dug cave. A dying Spanish soldier named Valverde reportedly discovered the site in the 1600s, leaving a manuscript with directions to the treasure. 

Despite hundreds of expeditions using Valverde's markings, the harsh mountain terrain, dense cloud forests, and treacherous bogs have claimed many treasure hunters' lives. Satellite imagery has recently identified several unusual formations in high-altitude lakes that could represent submerged structures, renewing interest in this legendary hoard.