Courtesy Isabella Stewart Gardner Museum
Rembrandt's "The Storm on the Sea of Galilee" was one of 13 artworks stolen from Boston's Isabella Stewart Gardner Museum in 1990, which still haven't been found. Check out the gallery for other valuable stolen artworks that authorities have yet to track down.
Cathédrale de Saint Bavon
The Ghent Altarpiece is the most frequently stolen artwork in history, having been stolen (all or in part) six times over a period of more than 600 years. Of the twelve panels that comprise the enormous altarpiece, one is still missing. Referred to as the "Righteous Judges" panel, it was stolen from the cathedral of St. Bavo in Ghent, Belgium in 1934. The theft was designed by Arsene Goedetier, a middle-aged stockbroker active in the cathedral community. He was not the actual thief, but designed the theft based on the plot of one of his favorite books, "The Hollow Needle" by Maurice LeBlanc. After many false leads and a protracted, failed attempt to ransom the panel back to the bishopric, it remains missing.
DIRECTMEDIA Publishing GmbH
Caravaggio's "Nativity with St. Francis and St. Lawrence" was stolen in 1969 from a church in Palermo by members of Cosa Nostra. It has never been recovered. Its theft prompted the foundation of the world's first dedicated art recovery police unit, called Tutela Patrimonio Culturale, or the Division for the Protection of Cultural Heritage. A mafia informant claimed that the Caravaggio was damaged in an earthquake and fed to pigs, but one hopes this is not the case.
Courtesy Polish Ministry of Culture, Art and National Heritage
"Portrait of a Young Man" is one of an estimated 5 million cultural heritage objects thought to have changed hands illegally during the Second World War. The masterpiece was taken from the Czartoryski Museum in Krakow in 1939, and destined for Hitler's home in Berlin. There it hung until 1945, when a Nazi official, Hans Frank, moved all of the paintings from Hitler's home to Wawel Castle in Krakow. It has not been seen since.
Courtesy WIKIMEDIA
Oxford University's Ashmolean Museum was burgled of its only Cezanne painting on Dec. 31, 1999. The sound of the break-in was masked because it was timed during a New Year's Eve fireworks display.
Courtesy Politie Rotterdam
Among many works stolen from the Rotterdam Kunsthal in October 2012, one can find Monet's "Waterloo Bridge, London" and "Charing Cross Bridge, London." The mother of one of the thieves claimed to have burned the stolen paintings in an attempt to hide the evidence, but hope remains that this is not the case.
Courtesy Web Gallery of Art
Hitler's favorite painting was "The Poor Poet" by Carl Spitzweg, a somewhat kitschy romantic painting that has one of art theft's most bizarre and serpentine stories. It was famously stolen in 1976 by the performance artist Ulay, who took it from the National Gallery in Berlin and hung it on the wall in the home of a poor, immigrant Turkish family as part of what he called a "political action." He immediately phoned the museum and turned himself in, explaining that he did this as a form of political protest. The painting was returned, but it was stolen again in 1989 (not by Ulay), and it has never been recovered.
JOSEPH EID/AFP/AFP/Getty Images
Thousands of illegally excavated archaeological objects have emerged from conflict zones in the Middle East over the last few years, with ISIS most overtly financing their activities through illicit trade in antiquities. While it is difficult to trace the sales of individual objects excavated in ISIS-occupied territories, it is thought that millions have been made through this dark art trade.
ullstein bild via Getty Images
A 1727 violin by famed luthier Antonio Stradviari was stolen in October 1995 from 91-year-old violinist Erica Morini's New York apartment. Stradivarius instruments have a habit of being stolen, and are each worth in the low millions, this one valued at $3 million.

Editor’s Note: Noah Charney is an international best-selling author and professor of art history. The views expressed here are the author’s own.

CNN  — 

Last month, the board of the Isabella Stewart Gardner Museum in Boston issued a statement that they would double the longstanding reward for the return of artworks stolen from their premises back in 1990. They are now offering a cool $10 million, but with a time limit: the deal is only good until Dec. 31.

This is the latest chapter in an epic saga of the biggest art theft in peacetime history. Thirteen artworks, valued at between $300-500 million (if sold legitimately on the open market) were lifted from the museum during an 81-minute window in the night after the St. Patrick’s Day revels, in 1990.

But while this reward doubling has made headlines, it is in my view an act more of frustration and desperation than a sign of impending solution.

When the original $5 million reward was set, it stirred up many leads, almost all of them dead ends. Myriad theories have swirled around who was behind this crime, for surely it was some larger organized crime group, more elaborate than just the two thieves disguised as policemen who bluffed their way into the museum, tricking security staff into opening the door without first checking with the police department.

The criminals got away with works including Rembrandt’s “The Storm on the Sea of Galilee,” Manet’s “Chez Tortoni” and Vermeer’s “The Concert” headlining their haul.

From Isabella Stewart Gardner Museum
On March 18, 1990, a pair of thieves disguised as Boston police officers entered the Isabella Stewart Gardner Museum and stole 13 priceless works of art. Twelve of the 13 pieces stolen are included in this gallery. Here you see one of five "Gouache" drawings by Edgar Degas.
From Isabella Stewart Gardner Museum
Upon entering, the intruders handcuffed the security guards, bound them with duct tape and left them in the basement, authorities said at the time. Pictured here is another of Degas' "Gouache" drawings.
From Isabella Stewart Gardner Museum
In less than 90 minutes, the bandits went through the museum's Dutch Room on the second floor and stole three Rembrandts, including the Dutch artist's only seascape, "Storm on the Sea of Galilee," along with Vermeer's "The Concert," five Degas drawings and other items, according to the museum's website. Pictured here: a third of Degas' "Gouache" drawings.
From Isabella Stewart Gardner Museum
Pictured here: a fourth of Degas' "Gouache" drawings.
From Isabella Stewart Gardner Museum
The fifth of Degas' "Gouache" drawings.
From Isabella Stewart Gardner Museum
"Landscape with an Obelisk" by Govaert Flinck
From Isabella Stewart Gardner Museum
Finial in the form of an eagle, gilt metal (bronze), French
From Isabella Stewart Gardner Museum
"A Lady and Gentleman in Black" by Rembrandt
From Isabella Stewart Gardner Museum
"Self-Portrait" by Rembrandt
From Isabella Stewart Gardner Museum
"The Storm on the Sea of Galilee," the only seasscape painted by Rembrandt.
From Isabella Stewart Gardner Museum
"The Concert" by Vermeer
From Isabella Stewart Gardner Museum
Chinese bronze beaker or Ku, A Chinese, Shang Dynasty, 1200-1100 B.C.ancient bronze beaker.

It was a complicated crime, too. There were details that suggested that the thieves knew exactly what they were looking for, that they had been instructed what to steal. They bypassed some works of equal or greater value (and perhaps more portable) than the art they took.

Tracking the haul

In 2013, on the 23rd anniversary of the Gardner art heist crime, the FBI held a press conference that sounded promising. They revealed some new information considered sensational by the media at the time.

As a professor specializing in the history of art crime, I get a lot of questions about this, the highest-profile art heist since the theft of the Mona Lisa. I know much about the soap opera that has been going on behind-the-scenes for many years, and I know how to read police press conferences and offers of reward.

While the press conference was interesting to update the general public, those of us in the know have been aware of all that was revealed, and for some time. In the press conference, couched in terms of an appeal for information, it was revealed that the the Gardner works appear to have been transported through Connecticut and Pennsylvania, and were offered for sale in Philadelphia.

This is useful information, as some theorists suggested that the works were destroyed, or had been shipped to Ireland, with IRA links to the theft.

That the art was offered for sale means that it was not immediately brought to the secret sitting room of some Thomas Crown or Dr. No (who, in the first James Bond film, has a hideout decorated in copies of real stolen art), where it has since remained. The careful phrasing of the press conference gave the impression that, while progress had been made in terms of learning some of the backstory, the investigation appeared – at least to me – to be no closer to the truth. Much is known, but not quite enough to recover the art.

The risks of rewards

For years now, driven by desire for glory – for the Gardner hoard is the Holy Grail for art detectives – and probably by a healthy interest in the eyeopening reward, a number of prominent investigators, in addition to the FBI, have been searching for clues, and have made enormous strides.

There are several fine books written about the ins-and-outs of the case, but the general consensus is this: The thieves, and those who know where the art is hidden, are dead. It remains to be seen if anyone still living knows the hiding place of the loot. That’s what the reward, and increased attempts at stirring public interest, aim to do.

Rewards, in the world of art theft, are sharp-handled swords. They can work well, or they can hurt the handler.

In 2008, a theft of gold statuary from the Museum of Anthropology at the University of British Columbia was solved thanks to the museum board posting a reward that was worth significantly more than the raw material value of the gold stolen. The thieves might have initially intended to melt their loot, thereby erasing the evidence. But the lure of the reward stayed their hand long enough for the police to catch them.

On the other hand, rewards can backfire. In 1975, 28 paintings were stolen from the Gallery of Modern Art in Milan. A reward was offered, the paintings were returned (by associates of the thieves) and paid (to associates of the thieves) and the art was placed back on display. Within months, thieves broke in again and stole 35 works, including many of the same paintings. It was likely the same thieves dipping into the same well twice. The fruits of this second theft have never been recovered.

Courtesy: C.Cordes/Herzog Anton Ulrich Museum
Rembrandt's drawing of a dog has been in the collection of the Herzog Anton Ulrich Museum in Braunschweig, Germany, since 1770, but was long thought to be the work of a different artist.
Courtesy Tajan
In 2016, a drawing attributed to Italian master Leonardo da Vinci was discovered in Paris, after a portfolio of works was brought to Tajan auction house for valuation by a retired doctor. It was valued at 15 million euros ($16 million).
Courtesy Tajan
The drawing also features sketches of light and shadows and notes on the back.
Courtesy National Trust for Scotland
While researching for an episode of BBC's "Britain's Lost Masterpieces" series at the National Trust for Scotland's Haddo House collection in Aberdeenshire , art historian Bendor Grosvenor and a team of experts found a painting that could have been painted by artist Raphael.
Reuters
In April 2016, a painting believed to be by Caravaggio was found in an attic in France. Experts said it could be worth $136 million.
Courtesy National Trust for Scotland
The work was originally purchased for $25 dollars at the end of the 19th century. It could now be worth $26 million.
JEAN-PIERRE MULLER/AFP/Getty Images
In 1911, Leonardo Da Vinci's "Mona Lisa" was stolen from the Louvre by an Italian who had been a handyman for the museum. The famous painting was recovered two years later.
courtesy Art Recovery
A statue called "Young Girl with Serpent" by Auguste Rodin was stolen from a home in Beverly Hills, California, in 1991. It was returned after someone offered it on consignment to Christie's auction house. Rodin, a French sculptor considered by some aficionados to have been the father of modern sculpture, lived from 1840 until 1917. His most famous work, "The Thinker," shows a seated man with his chin on his hand.
AFP/Getty Images
Picasso's "La Coiffeuse" ("The Hairdresser") was discovered missing in 2001 and was recovered when it was shipped from Belgium to the United States in December 2014. The shipper said it was a $37 piece of art being sent to the United States as a Christmas present. The feds say it was actually a stolen Picasso, missing for more than a decade and worth millions of dollars.
ANDREAS SOLARO/AFP/Getty Images
Italy's Culture Ministry unveils two paintings by the French artists Paul Gauguin and Pierre Bonnard on April 2, 2014. The paintings, worth millions of euros, were stolen from a family house in London in 1970, abandoned on a train and then later sold at a lost-property auction, where a factory worker paid 45,000 Italian lire for them -- roughly equivalent to 22 euros ($30).
PAUL J. RICHARDS/AFP/Getty Images
A Renoir painting finished in the 1800s, loaned to a museum, reported stolen in 1951 and then bought at a flea market in 2010 has to be returned to the museum, a judge ruled on January 10, 2014. The 5½-by-9-inch painting, titled "Landscape on the Banks of the Seine," was bought for $7 at a flea market by a Virginia woman. The estimated value is between $75,000 and $100,000.
Courtesy Interpol
Seven famous paintings were stolen from the Kunsthal Museum in Rotterdam, Netherlands, in 2012, including Claude Monet's "Charing Cross Bridge, London." The paintings, in oil and watercolor, include Pablo Picasso's "Harlequin Head," Henri Matisse's "Reading Girl in White and Yellow," Lucian Freud's "Woman with Eyes Closed" and Claude Monet's "Waterloo Bridge," seen here. Works by Gauguin and Meyer de Haan were also taken.
New York County DA Office
Eight months after Salvador Dali's "Cartel de Don Juan Tenorio" was stolen in a New York gallery, a Greek national was indicted on a grand larceny charge in 2013.
Courtesy wga.hu
In 1473, Hans Memling's "The Last Judgment" was stolen by pirates and became the first documented art theft.
Hulton Archive/Getty Images
Adam Worth, the inspiration for Sir Arthur Conan Doyle's diabolical character Moriarty, stole "Georgiana, Duchess of Devonshire," painted by Thomas Gainsborough in 1876.
REUTERS/Chris Pizzello /Landov
Among their many crimes, the Nazis plundered precious artworks as they gained power during World War II. "Adele Bloch-Bauer I," by Austrian artist Gustav Klimt, was confiscated from the owner when he fled from Austria.
REUTERS /PHILIP SEARS /LANDOV
Many works of art that were taken by the Nazis were never recovered. Others were returned after years of legal battles. "Christ Carrying the Cross," by Italian artist Girolamo de' Romani, was returned to his family in 2012.
REUTERS/Handout /Landov
"The Scream" was one of two Edvard Munch paintings that were stolen from the Munch Museum in Oslo, Norway, in 2004.
REUTERS/Nelson Antoine /Landov
In 2007, Pablo Picasso's oil painting ''Portrait of Suzanne Bloch" was taken from the Sao Paulo Museum of Art. It was recovered two years later.

There is also the complicated issue of how to swap the stolen art for the reward without granting illegal amnesty to the thieves, and without appearing to be paying a ransom, which is illegal in many countries.

So, will the lure of $10 million, and a closing window of opportunity, suddenly shake the art out of the woodwork, and get results, when $5 million led to no tangible results? Anyone, aside from the thieves themselves, is eligible for the full reward, but only if all 13 objects are returned in acceptable condition.

The answer is likely no, for $5 million is already so robust a reward, so far beyond the amount that thieves could possibly get for such famous art on the black market (where experts estimated that stolen art, if a buyer can be found at all, goes for around 7-10% of its estimated legitimate auction value, with more famous works all but impossible to sell, full stop), that doubling it does not suddenly provide an incentive that had previously been absent.

I have no doubt that the art will eventually be found. But it will be a matter of luck, of stumbling on its hiding place at some unknown point in the future, of accidentally pricking oneself while wading through a haystack, and thereby finding the lost needle.

Editor’s note: An earlier version of this story contained unsupported details regarding the night of the heist and subsequent investigations, which have now been removed.