US President Donald J. Trump (L) gives a thumbs-up next to First Lady Melania Trump as they attend a ceremony at the Pentagon during the 18th anniversary commemoration of the September 11 terrorist attacks, in Arlington, Virginia, 11 September 2019. (Photo by Kevin Dietsch/EPA/EFE/Pool)





Britain's Prime Minister Boris Johnson attends a year six history class with pupils during a visit to Pimlico Primary school in London, Britain, September 10, 2019. (Photo by Toby Melville/Pool via Reuters)





A person runs after throwing a petrol bomb at PSNI vehicles, after a security alert was upturned due to a suspicious package found in Creggan Heights, Derry, Northern Ireland on September 9, 2019 in this still image obtained from a social media video. (Photo by Derry Footage via Reuters)





Photo released by Noticias Argentinas of protesters clashing with riot police outside the Social Development Ministry building in Buenos Aires on September 11, 2019. Social organizations set up an overnight camp in front of the ministry's building to call on the government to declare a food emergency. (Photo by Damian Dopacio/Noticias Argentinas/AFP Photo)





Motorcyclists drive with an “Estelada” (Catalan separatist flag) attached to their bike on Catalonia's national day “La Diada” in Barcelona, Spain on September 11, 2019. (Photo by Juan Medina/Reuters)





An Ukranian tourist poses for a snapshot with a Catalan independence flag during the Catalan National Day in Barcelona, Spain, Wednesday, September 11, 2019. The traditional September 11, called “Diada”, marks the fall of Barcelona to Spanish forces in 1714. (Photo by Bernat Armangue/*AP Photo)





Men dressed in costume shoot their rifles during a performance to celebrate the Catalan National Day in Barcelona, Spain, Wednesday, September 11, 2019. The traditional September 11, called “Diada”, marks the fall of the Catalan capital to Spanish forces in 1714. (Photo by Emilio Morenatti/AP Photo)





People gather at a shopping mall in the Shatin area of Hong Kong on September 11, 2019, to sing a recently penned protest song titled “Glory to Hong Kong” which has been gaining popularity in the city. (Photo by Nicolas Asfouri/AFP Photo)





Delegates socialise in front of a large display on the SAAB stand on day two of the DSEI arms fair at ExCel on September 11, 2019 in London, England. The biennial Defence and Security Equipment International (DSEI) is the world's largest arms fair and is held in London's Docklands area. (Photo by Leon Neal/Getty Images)





Buddhist monks ride in a tuk-tuk in Phnom Penh, Cambodia on September 11, 2019. (Photo by Tang Chhin Sothy/AFP Photo)





A Mercedes 300 SL Gullwing Roadster made of Teak wood is displayed at the IAA Auto Show in Frankfurt, Germany, Wednesday, September 11, 2019. (Photo by Michael Probst/AP Photo)





SiriusXM Town Hall with Jennifer Lopez hosted by Hoda Kotb at the SiriusXM Studios on September 10, 2019 in New York City. (Photo by Cindy Ord/Getty Images for SiriusXM)





Dancers of China's Peacock Contemporary Dance Company perform Yang Liping's Rite of Spring during the International Contemporary Dance Festival DANCEINVERSION on the stage of Bolshoi Theatre in Moscow, Russia on September 10, 2019. (Photo by Shamil Zhumatov/Reuters)





Actress Renee Zellweger attends the premiere of “Judy” during the 2019 Toronto International Film Festival Day 6, on September 10, 2019, in Toronto, Ontario. (Photo by Valerie Macon/AFP Photo)





Cara Delevingne poses onstage for Savage X Fenty Show Presented By Amazon Prime Video – Show Sneak Peak at Barclays Center on September 10, 2019 in Brooklyn, New York. (Photo by Dimitrios Kambouris/Getty Images for Savage X Fenty Show Presented by Amazon Prime Video)