A zebra rubs its head against another at London Zoo, London, Britain, August 22, 2019. REUTERS/Toby Melville

A blue agave is pictured in Tequila, Jalisco, Mexico September 7, 2017. Picture taken on September 7, 2017. REUTERS/Carlos Jasso

Silver product is pictured in a second-hand silverware shop in Bordeaux, France, January 25, 2018. REUTERS/Regis Duvignau

'Supermoon' full moon reflections are seen on the windows of a business building in Ronda, southern Spain January 1, 2018. REUTERS/Jon Nazca

'Supermoon' full moon reflections are seen on the windows of a business building in Ronda, southern Spain January 1, 2018. REUTERS/Jon Nazca

'Supermoon' full moon reflections are seen on the windows of a business building in Ronda, southern Spain January 1, 2018. REUTERS/Jon Nazca

The 'supermoon' full moon is seen through Christmas lights in Valletta, Malta, January 1, 2018. REUTERS/Darrin Zammit Lupi

The 'supermoon' full moon is seen through Christmas lights in Valletta, Malta, January 1, 2018. REUTERS/Darrin Zammit Lupi

The 'supermoon' full moon is seen through Christmas lights in Valletta, Malta, January 1, 2018. REUTERS/Darrin Zammit Lupi

The 'supermoon' full moon is seen through Christmas lights in Valletta, Malta, January 1, 2018. REUTERS/Darrin Zammit Lupi

Diving – 17th FINA World Aquatics Championships – Women's 3m Springboard Semifinal – Budapest, Hungary – July 20, 2017 – Jennifer Abel of Canada competes. TPX IMAGE OF THE DAY

Diving – 17th FINA World Aquatics Championships – 10 m Platform Synchro Women preliminary – Budapest, Hungary – July 16, 2017 – Qian Ren and Yajie Si of China compete. REUTERS/Michael Dalder TPX IMAGES OF THE DA

Diving – 17th FINA World Aquatics Championships – 10m Platform Synchro Women final – Budapest, Hungary – July 16, 2017 – Valeriia Belova and Iuliia Timoshinina of Russia compete. REUTERS/Michael Dalder TPX IMAGES OF THE DAY

Diving - 17th FINA World Championships - Mixed 10m Synchro Platform Final - Budapest, Hungary - 15 July, 2017 - Mi Rae Kim and Il Myong Hyon of North Korea compete. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY

Diving - 17th FINA World Championships - Mixed 10m Synchro Platform Final - Budapest, Hungary - 15 July, 2017 - Valeriia Liulko and Maksym Dolgov of Ukraine compete. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY

Swimming- European Aquatics Championships- London, Britain, 12/5/2016. Denmark's Andreas Larsen and Martin Christensen compete during the diving men's synchronized platform final event. REUTERS/Andrew Boyers TPX IMAGES OF THE DAY

Swimming- European Aquatics Championships- London, Britain, 9/5/2016. Vadim Kaptur of Belarus competes during the diving team event. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY

Duncan Holden of the Tate poses with three paintings of Edvard Munch's "Weeping Woman" series at the Tate Modern in London's Southbank, June 26, 2012. This is the first time all six paintings of Munch's Weeping Woman series are shown together and they form part of the major exhibition of his paintings and drawings at the art museum. The exhibition opens on June 28 and will run until October 14, 2012. REUTERS/Andrew Winning (BRITAIN - Tags: ENTERTAINMENT SOCIETY)

Technician Humberto Duran inspects pictures taken by a camera mounted on a mobile robot-like structure as its moves across Pablo Picasso's 'Guernica' painting at the Reina Sofia Museum in Madrid February 28, 2012. Experts have long been concerned about the health of Picasso's "Guernica," one of the world's most iconic paintings but one which is diagnosed as extremely delicate after a hectic life. A mobile, robot-like structure, using advanced infrared and ultraviolet photographic technology, is taking thousands of microscopic shots of the painting to allow analysts to penetrate the work like never before and see its real condition. The mechanism has been constructed precisely so that the "Guernica" is not endangered in any way by having to be moved to a conservation laboratory, where normally such investigative work would be done. REUTERS/Sergio Perez (SPAIN - Tags: ENTERTAINMENT SCIENCE TECHNOLOGY)

Caroli Golubytskyi of Germany (L) and Nzingha Prescod of the U.S. compete during their qualification foil event at the World Fencing Championships in Catania October 11, 2011. REUTERS/Tony Gentile (ITALY - Tags: SPORT FENCING TPX IMAGES OF THE DAY)

A visitor wearing a red nose passes a painting titled "Desire" by Andrea Fumagalli at the opening of an exhibition featuring works by contemporary Italian artists in St. Petersburg July 21, 2011. The exhibition is held as part of a year of cultural exchange between Italy and Russia. REUTERS/Alexander Demianchuk (RUSSIA - Tags: ENTERTAINMENT POLITICS)

Germany's Uschi Freitag competes in the preliminary round of the women's 1m springboard diving event at the 14th FINA World Championships in Shanghai July 17, 2011. REUTERS/Christinne Muschi (CHINA - Tags: SPORT DIVING IMAGE OF THE DAY)

France's Damien Cely competes in the preliminary round of the men's 1m springboard diving event at the 14th FINA World Championships in Shanghai July 16, 2011. REUTERS/David Gray (CHINA - Tags: SPORT DIVING SWIMMING IMAGE OF THE DAY)

Visitors observe a painting during the opening of "Pictorial Abstraction. European and American Art Tendencies 1949-1969" at the Guggenheim Museum in Bilbao June 14, 2011. The exhibition, featuring eighty works by over sixty artists including Jackson Pollock, Antoni Tapies, William de Kooning and Victor Vasarely, covers trends in abstract art such as Art Brut, Abstract Expressionism and Art Informel.
REUTERS/Vincent West (SPAIN - Tags: SOCIETY)

Visitors observe the 1967 painting "Harran II" by U.S. artist Frank Stella following the opening of "Pictorial Abstraction. European and American Art Tendencies 1949-1969" at the Guggenheim Museum in Bilbao June 14, 2011. The exhibition, featuring eighty works by over sixty artists including Jackson Pollock, Antoni Tapies, William de Kooning and Victor Vasarely, covers trends in abstract art such as Art Brut, Abstract Expressionism and Art Informel.
REUTERS/Vincent West (SPAIN - Tags: SOCIETY)

Visitors observe a painting during the opening of "Pictorial Abstraction. European and American Art Tendencies 1949-1969" at the Guggenheim Museum in Bilbao June 14, 2011. The exhibition, featuring eighty works by over sixty artists including Jackson Pollock, Antoni Tapies, William de Kooning and Victor Vasarely, covers trends in abstract art such as Art Brut, Abstract Expressionism and Art Informel.
REUTERS/Vincent West (SPAIN - Tags: SOCIETY)

Visitors observe "Untitled", a 1952-3 painting by U.S. artist Mark Rothko during the opening of "Pictorial Abstraction. European and American Art Tendencies 1949-1969" at the Guggenheim Museum in Bilbao June 14, 2011. The exhibition, featuring eighty works by over sixty artists including Jackson Pollock, Antoni Tapies, William de Kooning and Victor Vasarely, covers trends in abstract art such as Art Brut, Abstract Expressionism and Art Informel.
REUTERS/Vincent West (SPAIN - Tags: SOCIETY)

A visitor observes the 1967 painting "Harran II" by U.S. artist Frank Stella following the opening of "Pictorial Abstraction. European and American Art Tendencies 1949-1969" at the Guggenheim Museum in Bilbao June 14, 2011. The exhibition, featuring eighty works by over sixty artists including Jackson Pollock, Antoni Tapies, William de Kooning and Victor Vasarely, covers trends in abstract art such as Art Brut, Abstract Expressionism and Art Informel.
REUTERS/Vincent West (SPAIN - Tags: SOCIETY)

Brazil's President Dilma Rousseff talks to Brazilian artist Romero Britto (R) in front of her portrait in Planalto Palace in Brasilia February 14, 2011. Britto painted and presented the portrait to Rousseff as a gift. REUTERS/Ueslei Marcelino (BRAZIL - Tags: POLITICS SOCIETY)

Brazil's President Dilma Rousseff stands next to her portrait, painted by Brazilian artist Romero Britto and presented to Rousseff as a gift, in Planalto Palace in Brasilia February 14, 2011. REUTERS/Ueslei Marcelino (BRAZIL - Tags: POLITICS SOCIETY)

A visitor looks at the painting "Boy and Dog in a Johnnypump, 1982" by U.S. artist Jean-Michel Basquiat (1960-1988) before the opening of the exhibition "Basquiat" at the Museum of Modern Art in Paris October 14, 2010. The retrospective exhibition, which commemorate the 50th anniversary of Basquiat's birth, opens to the public October 15, 2010 and runs until January 30, 2011. REUTERS/Benoit Tessier (FRANCE - Tags: ENTERTAINMENT)

Pedestrians smile as they walk past a painting titled "The Faces" on an outer wall of a construction site of the Seoul City Hall in central Seoul July 26, 2010. South Korea's economic growth slowed less than expected in the second quarter as capital spending jumped and consumption grew, data showed on Monday, reinforcing expectations for an additional interest rate increase soon. REUTERS/Jo Yong-Hak (SOUTH KOREA - Tags: BUSINESS SOCIETY IMAGES OF THE DAY)

A visitor looks at paintings by U.S. singer Marilyn Manson in Vienna's Kunsthalle June 28, 2010. An exhibition showing paintings by Manson will open on Tuesday. REUTERS/Leonhard Foeger (AUSTRIA - Tags: ENTERTAINMENT)

Three-year-old artist Aelita Andre poses with some of her paintings on display at the Art Melbourne 2010 exhibition April 23, 2010. Andre, whose work is in major collections across Europe, Asia and the United States, recently sold a painting to an overseas buyer for AUD$28,000 ($26,000). REUTERS/Mick Tsikas (AUSTRALIA - Tags: SOCIETY)

Three-year-old artist Aelita Andre poses with some of her paintings on display at the Art Melbourne 2010 exhibition April 23, 2010. Andre, whose work is in major collections across Europe, Asia and the United States, recently sold a painting to an overseas buyer for AUD$28,000 ($26,000). REUTERS/Mick Tsikas (AUSTRALIA - Tags: SOCIETY IMAGES OF THE DAY)

Canadian Opposition and Liberal Party leader Michael Ignatieff is silhouetted against an abstract painting following a news conference during a visit to Vancouver, British Columbia September 4, 2009. REUTERS/Andy Clark (CANADA POLITICS)

Homme A L'Epee by Pablo Picasso is seen at Christie's auctioneers in London June 18, 2009. The work, which carries an estimate of between £5-7 million pounds ($8.1 million - $11.4 million) is part of an Impressionist and Modern Art Sale that will take place at Christie's later this month. REUTERS/Kieran Doherty (BRITAIN ENTERTAINMENT)

Visitors look at paintings "Komposition VIII" (1923, L) and "Auf Weiss II" (1923) by Russian-born artist Wassily Kandinsky, the founder of abstract painting, at Centre Georges Pompidou museum in Paris April 6, 2009. The exhibition "Kandinsky" will run from April 8 to August 10, 2009. Picture taken on slow shutter speed. REUTERS/Philippe Wojazer (FRANCE ENTERTAINMENT)

Ernst Ludwig Kirchner's "Berlin Street Scene" 1880/1938, is seen during a preview of the "Brucke: The Birth of Expressionism in Dresden and Berlin, 1905-1913" exhibition at the Neu Galerie in New York February 25, 2009. Picture taken February 25, 2009. REUTERS/Shannon Stapleton (UNITED STATES)

Ernst Ludwig Kirchner's 1909-1910 painting, "Marzella", is displayed during a preview of the "Brucke: The Birth of Expressionism in Dresden and Berlin, 1905-1913" exhibition at the Neue Galerie in New York February 25, 2009. REUTERS/Shannon Stapleton (UNITED STATES)

Ernst Ludwig Kirchner's 1908-1919 painting, "Street, Dresden" is displayed during a preview of the "Brucke: The Birth of Expressionism in Dresden and Berlin, 1905-1913" exhibition at the Neue Galerie in New York February 25, 2009. REUTERS/Shannon Stapleton (UNITED STATES)

Karl Schmidt-Rotluff's 1910 painting, "Corner of the Park," is displayed during a preview of the "Brucke: The Birth of Expressionism in Dresden and Berlin, 1905-1913" exhibition at the Neue Galerie in New York February 25, 2009. REUTERS/Shannon Stapleton (UNITED STATES)

A painting by Alexej von Jawlensky entitled "Schokko (Schokko mit Tellerhut)" is seen at Sotheby's auctioneers, ahead of their February Impressionist and Modern Art sale where it is expected to fetch £6,500,000 - 8,500,000, in London January 29, 2008. REUTERS/Stephen Hird (BRITAIN)

Artist Tim Hawkinson of the U.S. stands below one of his artworks titled "Balloon Self-Portrait" ahead of his exhibition at Sydney's Museum of Contemporary Art (MCA) December 10, 2007. Hawkinson, who is from Los Angeles, is exhibiting in Australia for the first time. His show features ten years of his work. REUTERS/Will Burgess (AUSTRALIA)

A dancer performs during the opening of Youth Voluntary at the Arab Region conference in Damascus July 10, 2007. REUTERS/Khaled al-Hariri (SYRIA)

Visitors walk near the work of Canadian group BGL of a mess of melted ice cream cones known as "Sculpture with Milk" at the so-called End of the World Biennial, in the world's southernmost city of Ushuaia, in this March 31, 2007 picture. As icebergs melt and sea levels rise at the north and south poles due to global warming, dozens of artists are installing and performing works in this small Argentine city on the island of Tierra del Fuego to highlight the damage being done. REUTERS/Enrique Marcarian (ARGENTINA)

A museum guide gestures near a display by U.S. artist Roy Lichtenstein during the "Roy Lichtenstein: from beginning to end" exhibition at Madrid's Juan March Foundation March 19, 2007. REUTERS/Susana Vera (SPAIN)

A photographer is reflected in a piece of art on press day at the 2nd Moscow Biennale of Contemporary Art in the Federation Tower in Moscow February 28, 2007. The Moscow Biennale officially opens March 1. REUTERS/Thomas Peter (RUSSIA)

People visit the art piece "Des Cartes" in Madrid February 23, 2007. "Des Cartes", created by artist Monica Rodriguez, consists of 224.000 traditional Spanish playing cards hanging from a wall more than 500 metre square (1,640 square feet). REUTERS/Susana Vera (SPAIN)

Visitors walk in front of a installation by German
artist Gerhard Merz at the Kunsthaus in Bregenz February 17, 2007. The exhibition with works of Gerhard Merz, Damien Hirst, Jeff Koons and Marcel Duchamp opens today and runs until May 15, 2007. REUTERS/Miro Kuzmanovic (AUSTRIA)