One of Andy Warhol's renowned Marilyn Monroe pictures has set a record for the most expensive 20th-century artwork ever sold at auction. At Christie's in New York on Monday evening, the 40-square-inch "Shot Sage Blue Marilyn," one of dozens of photographs the artist took of Monroe in the 1960s, sold for a record $195 million. Christie's described "Shot Sage Blue Marilyn" as "one of the rarest and most transcendent images in existence" before the auction. It has previously been displayed in the Guggenheim Museum in New York, the Centre Pompidou in Paris, and the Tate Modern in London. The auction company had previously stated that bids "in the vicinity of" $200 million were expected. Along with his famous paintings of Campbell's soup cans, Warhol's vivid copies of Monroe's photo portrait — originally a publicity still from her 1953 film "Niagara" — are among his most recognized works. He began making them in 1962, shortly after Monroe's death, using a method called silkscreen printing, which duplicates images on paper or canvas using a layer of fine-mesh silk as a stencil. The Pop artist created multiple variations of Monroe's portrait in various colours and configurations, as he did with other renowned individuals such as Elvis Presley and Chinese leader Mao Zedong. "Marilyn Diptych," owned by British gallery organisation Tate, is one of the most well-known, with Warhol printing a grid of 50 portraits across two canvases. Other works include "Gold Marilyn Monroe" at the Museum of Modern Art, which shows a single image printed against a gold background, and "Shot Marilyns," which included the artist shooting photographs of the actress through the skull with bullets. According to Christie's, he created a "more refined and time-intensive" new procedure in 1964 that was "antithetical to the mass production he was best known for." Before abandoning the technique, he employed it to make a small number of portraits that year — a rare collection of works to which "Shot Sage Blue Marilyn" belongs. While a handful of paintings are thought to have sold for more than $200 million in private sales (including works by Abstract Expressionist painters Willem de Kooning and Jackson Pollock), Leonardo da Vinci's "Salvator Mundi," which sold for more than $450 million in 2017, is the only painting to have done so at auction. The previous auction record for a 20th-century artwork was set in 2015 when Pablo Picasso's "Les Femmes d'Alger (Version O)" sold for $179.4 million. "Silver Car Crash (Double Disaster)," which depicts the damaged aftermath of a road crash and sold for more than $105 million almost a decade ago, holding the previous auction record for a Warhol work. Several other Marilyn portraits by the artist have sold for large sums at auction in recent years, with "White Marilyn" from 1962 selling for $41 million in New York in 2014. Meanwhile, "Shot Sage Blue Marilyn" passed through the hands of a number of prominent gallerists and collectors until being acquired by the late Swiss art dealer Thomas Ammann. According to a press statement, the image was auctioned off by the Thomas and Doris Ammann Foundation Zurich, a charity organisation established in his (and his sister's) names that will utilise the earnings to finance health and education projects for children around the world. Christie's chairman of 20th and 21st century art, Alex Rotter, characterised the work as "the absolute pinnacle of American Pop" and "the most significant 20th century painting to come to auction in a generation" in a press statement prior to the sale. "Warhol's 'Marilyn,' which stands with Botticelli's 'Birth of Venus,' Da Vinci's 'Mona Lisa,' and Picasso's 'Les Demoiselles d'Avignon,' is definitely one of the greatest paintings of all time," he continued. The painting was one of four Warhols in the Ammanns' collection that went up for auction on Monday evening. One of his iconic "Flowers" silkscreen prints sold for $15.8 million, while "GE/Skull," which he created with the late Jean-Michel Basquiat, sold for more than $4.6 million. Meanwhile, Warhol's artwork "Heinz Tomato Ketchup Box" sold for $478,000. Works by Robert Ryman, Alberto Giacometti, and Lucian Freud were also auctioned off. Paintings by American artist Cy Twombly, "Untitled" and "Venere Sopra Gaeta," which sold for $21 million and over $17 million respectively, were among the top sellers.