Written by CNN Staff

Whether you're buying, selling or merely watching the drama unfold, a blockbuster auction is a thrilling thing. And this year has seen an extraordinary number of attention-grabbing auctions take place across the globe.

While art and diamond auctions typically dominate the headlines, the market is rich with other more unexpected objects ranging from the sublime to the ridiculous.

Here are some of the most unusual items to cross the auction block this year.

Largest freshwater pearl

Venduehuis

The world's largest known freshwater pearl , known as "The Sleeping Lion," sold for €320,000 ($374,000) at the Venduehuis auction house in the Netherlands in May. Measuring more than 2.7 inches long, and weighing over 4 ounces, the pearl is of Chinese origin and is believed to have formed in the 1700s during the Qing dynasty. Along with its size and animal-like appearance, the pearl is renowned for its approximately 300-year history, during which it changed hands between colonial merchants, noble jewelers and European royals, including Catherine the Great.

Moon rocks

Sothebys

Three tiny moon rocks , brought to Earth by the Soviet Luna-16 Mission in 1970, were sold for $855,000 at Sotheby's New York in November. The only known documented lunar rocks in private hands, they were first presented to Nina Ivanovna Koroleva, the widow of former Soviet space program director Sergei Pavlovich Korolev as a gift on behalf of the USSR. In 1993, Koroleva sold the rocks to Sotheby's, marking the "the first time that a piece of another world had ever been offered for sale to the public," according to the auction house.

Stephen Hawking's wheelchair

Courtesy Christie's

The earliest surviving wheelchair of Stephen Hawking sold for £296,750 ($393,000) at a Christie's online auction in November, with the proceeds going to the Stephen Hawking Foundation and the Motor Neurone Disease Association. The late scientist was known for his occasionally wild driving, having reportedly run over Prince Charles's toes during a meeting in 1977 (a biography later claimed that he regretted not doing the same to Margaret Thatcher). This item was in use from the 1960s until the early 1990s, after which Hawking was no longer able to operate wheelchairs with his hands. Thomas Venning, head of the books and manuscripts department at Christie's London, said it was "literally and figuratively one of the most-traveled wheelchairs in history."

All-diamond ring

Sotheby's

An entire ring cut from a single diamond, created by Apple's chief design officer Jony Ive and industrial designer Marc Newson, went under the hammer for $256,000 in December. The item has between 2,000 and 3,000 facets, a number never previously seen in a single-diamond piece, according to auction house Sotheby's. The ring was auctioned off in Miami, with the proceeds donated to (RED), an HIV/AIDS charity set up by singer Bono and activist Bobby Shriver.

3,000-year-old Assyrian sculpture

CHRISTIE'S IMAGES LTD. 2018

A rare, 3,000-year-old sculpture fetched $31 million at Christie's New York in October, breaking the world record for Assyrian art and tripling its pre-sale estimate of $10 million. The solid slab of gypsum, excavated in the 19th century in present-day Iraq, depicts a deity resembling King Ashurnasirpal II. In the lead up to the auction, the Iraqi Ministry of Culture called for the panel to be returned to Iraq, and activists proposed a protest outside Christie's during the sale. A spokesman for Christie's said that although the auction house was "sensitive to claims for restitution by source countries," it had been reassured by law enforcement authorities that there was no legal basis for Iraq's claim.

5,655-carat emerald

Gemfields

5,655-carat emerald crystal , unearthed in Zambia in October, fetched $28.4 million at auction in Singapore in November. Weighing more than 1.1kg (almost 2.4lbs), the emerald has "remarkable clarity and a perfectly balanced golden green hue" according to then-owner, Gemfields. But the gem is not the largest treasure to have been found in the company's mines. In 2010, miners at its Zambia-based operation found a 6,225-carat emerald named the "elephant" due to its massive size.

$1.1M whisky

Bonhams

A rare bottle of whisky sold for more than $1.1 million at Bonhams in Edinburgh, Scotland in October. The 60-year-old Macallan Valerio Adami 1926 became the most expensive whiskey ever to be sold at auction. The bottle is one of a limited edition of 24, though it is unknown how many of them remain, according to Bonhams. The item broke a record set just months earlier, when another practically identical bottle went for a little over $1 million in Hong Kong.

AI-produced artwork

Courtesy Obvious

"Edmond de Belamy" made history by becoming the first AI-produced artwork to be sold at auction. It fetched $432,500 at Christie's in New York in October, dramatically exceeding its top estimate of $10,000. Although the print is signed "min G max D x [log (D(x))] + z [log(1 -- D (G(z)))]" (after a section of the algorithm's code), it was conceived by Obvious, a Paris-based trio fascinated by the artistic potential of machine learning. To produce the artwork, Obvious fed images of 15,000 real portraits into a two-part algorithm. After reviewing the submissions, the first algorithm began generating its own portraits until it created original works able to fool the second into thinking it was man-made.

Winnie-the-Pooh original map

Sotheby's

An original drawing of Winnie-the-Pooh's map sold for almost $600,000 at Sotheby's in July, setting a new auction record for a book illustration. The Hundred Acre Wood map , created by E.H. Shepard in 1926, was "possibly the most famous map in children's literature" according to the auction house. The map featured locations that were part of Pooh's adventures, including "Pooh Trap for Heffalumps" and "where the Woozle wasn't." The auction also included four more sketches by Shepard.

Dinosaur skeleton

Stephane de Sakutin/AFP/Getty Images

The skeleton of a 150-million-year-old dinosaur sold for more than $2.36 million in Paris in June. Measuring 2.6 meters (8.5 feet) tall and almost 9 meters (30 feet) long, the fossil closely resembles an Allosaurus, though scientists weren't able to confirm the exact species of the dinosaur. The artifact was in reportedly good condition, with around 70% of the skeleton remaining intact. The sale was the latest in a series of high-profile paleontological sales arranged by auction house Aguttes. In 2016, it sold a confirmed Allosaurus skeleton for $1.32 million, while last year, a complete mammoth skeleton went under the hammer for more than $641,000.

Eiffel tower staircase

PHILIPPE LOPEZ/AFP/AFP/Getty Images

A section of the Eiffel Tower's staircase sold for €169,000 ($191,000) by Artcurial auction house in November. This 25-step, 4.3-meter tall spiral staircase once helped link the tower's second and third levels before elevators were installed in 1983. It was not the first time that the auction house presented a slice of the Eiffel Tower. In 2013, a 3.5-meter-tall section was sold for €220,000, and in 2016, another block of stairs fetched €523,800. Segments of the staircase can now be found in locations around the world, including Japan, New York and Switzerland.

Queen's Rolls-Royce

Tim Graham/Tim Graham Photo Library/Tim Graham/Getty Images

Queen Elizabeth II's Rolls-Royce sold for more than $1 million (£800,000) at a London auction in September. The 1953 Rolls-Royce Phantom IV State Landaulette , that the Queen used on state occasions, was kept by the royal family for over 40 years. It is also the same model that Meghan, Duchess of Sussex, used on her wedding day in May. "There were only 18 of the Phantom IVs built, and they were bought by heads of state or dignitaries," Bonhams' co-chairman, Malcolm Barber, told CNN in a phone interview before the sale. "None are exactly the same, and they're all built to special order. Even if you are a Rolls-Royce collector, you wouldn't have anything similar, because each has its own identity."

Self-destructing Banksy

Jack Taylor/Getty Images