A bomb-laden Su-25 jet at the Hmeimim air base in December 2015. Russia's lease agreement obliged Assad’s military to safeguard the perimeter of the Hmeimim base, while giving Moscow legal jurisdiction over the facilities inside. Negotiating perimeter protection from Syria’s new rulers will be vital for the Russian bases in an era of wire-controlled drones immune to jamming. (Photo by AP Photo)

West Bromwich Albion's Saido Berahino (front) is challenged by Manchester City's Fernandinho during their English Premier League soccer match at The Hawthorns in West Bromwich, central England December 4, 2013. (Photo by Eddie Keogh/Reuters)

The summit of one of Europe's tallest mountains glows like the flame of a candle as the sun rises on a clear morning. The Matterhorn, famous for appearing on bars of Toblerone chocolate bars, reflects the vivid orange light at 5.37am. (Photo by Margarethe Jaeger/Solent News & Photo Agency)

Brazilian revelers pose during Carnival celebrations along Ipanema beach on February 18, 2012 in Rio de Janiero, Brazil. (Photo by Mario Tama/Getty Images)

Comedian Jeffrey Ross (C) arrives at Comedy Central's Roast of Charlie Sheen held at Sony Studios on September 10, 2011 in Los Angeles, California. (Photo by Christopher Polk/Getty Images)

Emma Raducanu of Great Britain hits a return to Belinda Bencic of Switzerland during their quarterfinals round match on the tenth day of the US Open Tennis Championships the USTA National Tennis Center in Flushing Meadows, New York, USA, 08 September 2021. The US Open runs from 30 August through 12 September. (Photo by Justin Lane/EPA/EFE)

Participants dressed as Santa Claus take part in the Great Edinburgh Santa Run on December 11, 2011 in Edinburgh, Scotland. Around a thousand people took part in the annual fundraising event, with all money raised being donated to the charity “When You Wish Upon a Star”. (Photo by Jeff J. Mitchell/Getty Images)