We assume that the high-end artworks sold at auction are real, reputable and legal, but this isn't always the case. Looting and lies, forgery and theft – plus the odd stunt – all play their part in this world where the stakes are high and the profit margins huge. With a Tutankhamun bust selling in the millions recently, leading to an impending court case, and a sold Banksy stencil shredding in front of the auction house's eyes, we take a look at the most controversial and heavily criticised auctions around the globe.

This auction came to an end before it actually started. Several paintings believed to be by little known fine artist but well known Nazi leader Adolf Hitler were amongst the items up for sale in the German town of Nuremberg earlier this year. Weidler auction house hoped to raise €45,000 ($50k/£41k) from the most expensive watercolour, even though the town's mayor called the sale "distasteful" regarding the 'artist's' atrocities. The collection also included a wicker chair with a swastika said to have been owned by the dictator. However, a few days before the scheduled sale, police confiscated the art works over forgery concerns.

A rock and roll auction caused a stir in 2017 when several intimate items, some of which Madonna still believed to be in her possession, were put up for auction at a New York store. These included worn underwear, a cheque book, unreleased songs, a used hairbrush and other "personally sensitive" memorabilia of the singer, as well as a letter in which she criticised Whitney Houston and Sharon Stone. Madonna took out an injunction against the sale and, in the end, a judge stopped it, deeming that the items had been stolen.

This 2017 online sale was the first of its kind and considered by some a flouting of legal regulations. South African rhino breeder John Hume put 500 kilograms of the endangered animal's horn online, but said he possessed a six-ton stockpile of the goods, which are usually traded on the black market. Although the auction later declared a disappointing number of sales, it was intimated that some were made. To even see the items on offer, a registration fee of $7,600 (£6.2k) had to be paid.

A 150-year-old replica of the guillotine caused some controversy in Paris in 2018 when it was sold to a French millionaire with a habit of collecting bizarre objects. The item, which was formerly on display at a museum of torture in the city, was criticised by human rights watchdogs due to the guillotine's history and usage as execution device. Having never been used to behead anyone, the replica sold for €8,008 ($8.9k/£7.3k).

A gruesome momento was up for sale in the UK last year, when Stalin’s death mask was offered to buyers in Canterbury, Kent. There is a strange quasi-religious thirst for relics that have followed the death of Communist leaders. The bronze mask, taken after the Soviet revolutionary's death in 1953 and believed to be one of 12 made, was auctioned along with two casts of Stalin's hands and sold for a whopping $17,200 (£13.5k), six times more than expected.

Earlier this year, a toothpaste lid from the 1880s featuring a Māori chief sparked some controversy. The item is deemed an object of cultural appropriation by many, and a form of ‘abuse’ by the chief’s ancestors. However, the lid is one of only two (from an original 144) in existence, and so commanded a high price – $21,622 (£17,462) according to New Zealand website NewsNow.

Last year, a piece of art – Portrait of Edmond de Belamy – created by an AI programme sold for more than double the combined price of the Andy Warhol print and Roy Lichtenstein bronze it hung opposite in Christie’s in New York. The abstract portrait was generated by an algorithm using a data set of 15,000 portraits painted between the 14th and 20th century. However, questions were raised when programmer Robbie Barratt claimed the piece was created using a code he had written and shared online. Makers of the AI artwork confirmed this, but stated that they had modified the code.

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Just one year after their divorce, the personal belongings of Rolling Stones star Ronnie Wood were put up for sale by his ex-wife Jo in 2012. Calling Wood "selfish", his former stepson arranged the auction, selling clothes and instruments for an estimated $487,000 (£400k) including a 1955 Fender Stratocaster guitar which fetched $60,800 (£50k). Wood in turn said he was "shocked and disappointed". The marriage had lasted for 23 years. The guitarist is now married to Sally Humphreys (pictured).

One of several UK councils who have now sold off public property to fill their coffers, Hertfordshire Council’s art sale this year drew criticism from arts organisations like Art Fund. As many as 450 works were taken from the Hertfordshire Schools Art Loan Collection which was started in the 1940s and aimed to give access to public artworks to children. Artist Bob and Roberta Smith OBE created a painting (pictured) in protest at the auction which was later submitted to the Royal Academy. 

In 2013, London residents halted the sale of the mural Slave Labour by guerrilla graffiti artist Banksy after it was prised from a wall in the English capital and reappeared in Florida, USA, where it was put up for auction. Community leaders demanded that the stolen work showing a child sewing union jack bunting be returned and stopped the sale. But in 2018, US artist Ron English (pictured) purchased the mural for $730,000 (£600k) and now plans to paint it over as he believes that street art "shouldn't be bought and sold".

Paris auction house Drouot also caused protests in 2013 when it went ahead with the sale of several Native American artefacts, including masks sacred to the Hopi people. A French magistrate ruled that the auction could go ahead, despite a case brought to the courts by the tribe. However, Survival International, which works to protect tribal groups, successfully acquired and returned one of the masks to the Hopi.

In 2014, seven masks of the Navajo people were put up for sale by Drouot auction house in Paris, despite attempted blocks from US government officials and the Native American tribe. Cleverly, the Navajo people sent a delegation to bid for the ritual masks, which they consider to be living, breathing beings, and were successful.

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Perhaps the most intentionally shocking auction in recent years was the sale of Banksy stencil Girl With Balloon in 2018. As the last hammer went down, a mechanism inside the gilt frame of the piece was set off and the artwork was shredded in front of the entire audience at Sotheby’s in London. The incident went viral however, which was good publicity both for the artist and the auction house. In fact, the spray paint and acrylic on canvas has even increased in value.

A statue of controversial Confederate General Robert E Lee sold earlier this year in Dallas for a whopping $1.4 million (£1.15m). It had previously been removed from a park in 2017 following vandalism – Robert E Lee is one of several historical military leaders held in high esteem by white supremacists. The memorial was sold subject to the agreement that the buyer cannot place it in public view.

In 2009, the sale of a bowl, several glasses and sandals belonging to Mahatma Gandhi went up for sale in New York. However, the auction was hotly contested by the Indian government claiming the articles belonged to the civil rights leader's home country. The items were finally purchased by Indian tycoon Vijay Mallya who planned to return the items to India. This is just one of several controversial Gandhi-related auctions – there was further outcry in 2012 when a piece of soil purportedly containing Gandhi’s blood went on sale.

Sotheby's in New York kicked up a lunar storm when it sold this bag containing traces of moon dust in 2017. The bag, stamped with the words 'Lunar Sample Return', was used by Neil Armstrong to gather rocks on the Apollo 11 mission in 1969, the first successful mission to earth’s satellite. NASA was unhappy with the sale, as the space agency had accidentally sold the bag to a private collector in 2014 for just $995 (£818) after the space agency confused it with another space bag from a later lunar landing. Prior to these sales, the bag had been discovered amongst the possessions of Max Ary, who had been indicted for stealing and selling museum artefacts in 2005.

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The sale of a 150-million-year-old dinosaur skeleton was disputed when it was auctioned in Paris in 2018. Paleontologists were furious, arguing that the prehistoric remains should be kept in "public trust" and not be sold to a private person. However, French auction house Aguttes went ahead with the sale and the bones of the Wyoming native known as Allosaurus were purchased by an unknown bidder for $2.3 million (£1.9m).

Each year, Safari Club International (SCI) holds an auction offering buyers the debatable opportunity to hunt more than 600 animals in 32 countries around the world. In 2017, the club raised $2.7 million (£2.2m) and over five days in 2018 brought tens of thousands of bidders to Las Vegas and even more online. SCI came to shady public attention in 2015 after one of its American members killed the protected lion Cecil in Zimbabwe, and again that same year when it auctioned a licence to shoot a rare black rhino.

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A letter in which Nobel prize winning scientist Albert Einstein called religion and belief in God "childish superstitions" sold at Christie’s in New York in 2018 for $2.89 million (£2.35m), nearly double its original valuation. The handwritten letter dated 3 January 1954 had been sent to religious philosopher Eric Gutkind. Einstein also wrote about his own Jewish identity that it is "like all religions, an incarnation of primitive superstition". Religious groups, it goes without saying, were up in arms.

Two auctioned paintings from the collection of artist Robert Indiana, creator of the iconic LOVE image, sparked dispute last year. On the day before the artist’s death in May, the organisation that had long represented him, Morgan Art Foundation, filed a suit against his caretaker Jamie Thomas, claiming Thomas had isolated the artist in his later years and exploited him. In his will, Thomas was named as executive director of the foundation responsible for Indiana’s art collection, worth around $50m (£41m).

Most recently, a sculpture of pharaoh Tutankhamun caused complaint when it was sold at auction by Christie’s in London. Egypt stated it would sue the auction house, with demands by the government that the statue be repatriated. It was claimed that the bust was looted from the Temple of Karnak in the 1970s and is state property. In turn, Christie’s said all possible checks on the work were carried out with due diligence. The case will now proceed to court.

Earlier this year, the auction of a drawing by Flemish master Rubens drew criticism when it was sold at Sotheby’s in New York to an unknown bidder. Nude Study of a Young Man with Raised Arms should have been offered to a Dutch museum, critics said, as it had been owned by the Dutch royals since the 19th century. Yet Princess Christina of the Netherlands sold it as a private asset rather than a public one.

Certainly anything involving dictator Adolf Hitler will cause controversy, but this statue of the kneeling fascist by Italian artist Maurizio Cattelan was deemed to be in particularly bad taste. Viewed from behind, the piece made using wax, polyester, resin and real human hair resembles a child in prayer, until you come forward and are face-to-face with the unmistakable visage. It was sold in 2016 for a record $17.2 million (£14m) to an anonymous buyer.

This 4,500-year-old statue was another sale made as a money-making scheme by a UK council. It was donated to Northampton Museum in 1880 by the second Marquis of Northampton, and many believed it should have remained there. However, after discovering its value in 2012, the council made the decision to sell it off less than two years later. It now resides at an unknown destination in the US after being sold to a private buyer for £15.8 million ($19m).

There was more uproar this year when Christie’s auctioned off $109 million (£89m) worth of Indian artifacts which many believe should not be privately owned but be repatriated and returned to India. This included a reproduction of the gold, 20-sided 'magic box' belonging to 18th century ruler Tipu Sultan (pictured), taken by the British after they killed him in 1799. Other stolen items from this haul abound, for example an automated tiger belonging to Tipu which is now held in the V&A Museum in London.

Discovered beneath an old mattress in France last year, this masterpiece was snapped up two days before it went under the hammer. It was authenticated by art expert Eric Turquin who claimed it to be the lost Caravaggio work Judith and Holofernes. However, Italian specialists have raised doubts, speculating that the work could potentially be a copy by Flemish artist Louis Finson. The painting was sold to an unidentified buyer for an undisclosed amount, but was valued at $170 million (£139m).

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Is this painting the most expensive disappointment in the world? Sold at auction for an eye-watering $450 million (£370m) in 2017, the Salvator Mundi said to be the work of Leonardo da Vinci has divided the art world. Specialists believe it was partly painted by the Italian master’s assistants. Despite having sold the oil portrait for the record price, former owner and billionaire Dmitry Rybolovlev now claims he was swindled by Sotheby's when purchasing it for $127.5 million (£104.8m) and is demanding $380 million (£312m) in damages.

The top auction sales of 2019 so far