A painting that had vanished in 1997 was discovered in the walls of the very gallery it was stolen from in 2019. The painting's disappearance had been one of the art world's biggest mysteries. "Portrait of a Lady" is a later work by the Austrian art nouveau master.

The last piece Austrian artist Gustav Klimt ever painted — "Lady with a Fan" — was still on his easel at the time of his death at the onset of the flu pandemic in 1918. Sotheby's has described the portrait as "the most valuable ever to have been offered at auction in Europe."

Fourteen-year-old Gustav Klimt entered the Vienna School of Arts and Crafts in 1876, and perfected the classical style of painting. He was a gifted draftsman able to depict details with photo-like precision. As a portraitist he captured the soul of the sitter.

Among his first commissions were the murals of Vienna's Burgtheater. In 1886, working as the group called the "Company of Artists," Gustav Klimt, his brother Ernst Klimt and Franz Matsch painted emblematic scenes of theater history on the staircase hall and ceiling of the building. In 1888, Emperor Franz Joseph bestowed them with the Golden Cross of Merit.

In 1887 Klimt became the first president of the Vienna Secession movement. The group of artists — among them the renowned architect Joseph Hoffmann — aimed to create a new style that broke away from tradition and democratized art. The arts were to unite to bring beauty into everyday life.

In 1894 Klimt was asked to paint three murals for the ceiling of the University of Vienna. Instead of painting historical allegories of medicine, philosophy and jurisprudence, the artist broke away from tradition and created dream-like scenes of sensuous nudes floating in a void. The painting above represents Medicine. All three works burned in the fire of Immendorf Castle in 1945.

His representation of Philosophy shows the victory of light over darkness. Klimt painted nude figures that pile up on the left edge of the canvas because of the lack of depth; a characteristic of modern art. They float through life and contort in despair with their eyes closed. Knowledge, at the bottom of the work, has her's wide open.

Klimt's famous golden period begins with the "Beethoven Frieze" and reaches its peek with "The Kiss" and "Portrait of Adele Bloch-Bauer I" (shown here). The latter is inspired by the Byzantine mosaic of Empress Theodora (A.D. 547) in the Church of San Vitale. Stolen by the Nazis in 1941, the painting was returned to the Bloch-Bauer heirs in 2006 and sold for a record sum that same year.

Flatness creeps into modern art to emphasize the characteristics and materials of the medium. Art shows its truth instead of creating an optical illusion. By adding gold to his paintings, Klimt wrapped his figures around in an aura of spirituality. This period is characterized by a mixture of expressionism and rich ornamentation.

Klimt studied the human form through hundreds of sketches. He drew mostly women of different shapes, and ages in multiple poses. His sensuous lines dig into the soul of the model, and have a similar effect to literature's stream of consciousness. Through form stripped to its bare minimum, Klimt opens a window into the human psyche.

Even though the subject of life and death has been depicted many times throughout history, Klimt managed to make it modern. In "Death and Life," death looks menacingly towards the stream of the living who float in a dream of color. As many artists of his time, Klimt has a particular interest in the inner world.

Thieves have stolen a collection of almost 500 gold coins from the Celtic Museum in Manching, Bavaria. The 2,000-year-old treasure was the museum's highlight. It is still unclear how the perpetrators were able to switch off the alarm systems. The police described the burglary as having been executed in a classic way, as in "a bad movie," while Bavaria's culture minister called it a "disaster."

The Green Vault in Dresden's Royal Palace is one of the most famous treasure chambers of Europe. Early in the morning of November 25, 2019, burglars broke into the museum and stole three sets of jewelry from the early 18th century. The works made up of diamond, ruby and emerald gems are seen as "priceless." German newspaper Bild called it "probably the biggest art theft since World War II."

The world's most famous portrait, Leonardo da Vinci's "Mona Lisa," was stolen in 1911. A young Italian named Vincenzo Peruggia took the painting from the Louvre in Paris. Dressed as a member of the museum staff, he was able to hide the relatively small painting under his work coat. It reappeared in 1913 after an art dealer alerted the police.

Rembrandt's portrait of "Jacques III de Gheyn" wasn't stolen from Britain's Dulwich Picture Gallery just once, but four times, namely in 1966, 1973, 1981 and 1986. That's why it came to be nicknamed the "Takeaway Rembrandt." Fortunately the painting has been recovered after each theft.

The burglary of 13 paintings from the Isabella Stewart Gardner Museum stirred international attention in 1990. Two men disguised as policemen broke into the building and removed the paintings, among them Edouard Manet's "Chez Tortoni" and Jan Vermeer's "Concert" (pictured). The empty picture frames are still hanging on the walls.

In 1991, a man managed to lock himself into a bathroom in the Van Gogh Museum in Amsterdam — unnoticed. With the help of a warden, he removed a total of 20 paintings, among them the Dutch painter's "Self-Portrait with Easel." However, police were able to recover the works from the getaway car just one hour later. The thieves were caught a few months later.

"Madonna of the Yarnwinder" by Leonardo da Vinci, valued at €70 million ($72 million), was stolen from a Scottish castle in 2003. Two thieves who entered an exhibition as tourists overpowered the security guard at Drumlanrig Castle and fled with the precious artwork. It remained lost for years until it was discovered during a raid in Glasgow in 2007.

Two paintings by expressionist Edvard Munch, "The Scream" and "Madonna," were stolen in Oslo in 2004. Two armed robbers invaded the Munch Museum and, witnessed by numerous visitors, ripped the paintings from the wall. Police were able to retrieve the two famous paintings. However, "The Scream" was damaged so badly during the incident that it could never be fully restored.

In 2008, armed thieves pilfered four paintings amounting to a total value of 180 million Swiss francs (€183 million, $189 million) from the collection Bührle in Zurich. "The Boy in the Red Vest" by Paul Cézanne, "Ludovic Lepic and His Daughters" by Edgar Degas, "Blossoming Chestnut Branches" by Vincent van Gogh, and "Poppy Field Near Vétheuil" by Claude Monet (pictured) all resurfaced later on.

In March 2017, a huge gold coin weighing 100 kilos was stolen from Berlin's Bode Museum. Just its sheer material value alone amounts to four million dollars. It is believed that the thieves found their way into the building through a window. The "Big Maple Leaf" coin originated in Canada. It is 53 cm high and 3 cm thick. On the front side, it bears an image of Queen Elizabeth II.