In this aerial view the officers' building and an auditorium stand at the former Soviet military base on January 26, 2017 in Wuensdorf, Germany. Wuensdorf, once called “The Forbidden City”, was the biggest base for the Soviet armed forces in communist East Germany from 1945 until the last Soviet troops left in the early 1990s following the end of the Cold War and the reunification of Germany. (Photo by Sean Gallup/Getty Images)

In this Wednesday, August 21, 1991 file photo, appreciative muscovites hand bread, sausages and flowers to a Soviet tank's driver who helped stop the failed hardline coup in Moscow, Russia. When a group of top Communist officials ousted Soviet leader Mikhail Gorbachev 30 years ago and flooded Moscow with tanks, the world held its breath, fearing a rollback on liberal reforms and a return to the Cold War confrontation. But the August 1991 coup collapsed in just three days, precipitating the breakup of the Soviet Union that plotters said they were trying to prevent. (Photo by Czarek Sokolowski/AP Photo/File)

Felix Guirola, 52, rides a homemade bike with an advertising banner in Havana, Cuba, July 20, 2016. The handyman, who loves heights, provides advertising space for companies on homemade bikes that tower up to 7.5 meters (24.61 ft). He rides them around Havana in an ingenious way of getting around strict marketing regulations in the Communist-ruled island. (Photo by Alexandre Meneghini/Reuters)

MiG-15 jet fighters are pictured in Kucova Air Base in Kucova, Albania on October 3, 2018. Albania retired its 224 Soviet- and Chinese-made MiGs in 2005, and since 2009 NATO neighbors Italy and Greece monitor its airspace. That led to economic decline in and around Kucova, which was called “Stalin City” during the era of Communist rule. (Photo by Florion Goga/Reuters)

Pedestrians and vehicles make their way past the Potala Palace early on a rainy morning in Lhasa, capital of the Tibet Autonomous Region in China, Saturday, September 19, 2015. Chinese officials have taken foreign journalists on a visit to the region, normally off-limits to them, weeks after Communist Party officials commemorated the 50th anniversary of the establishment of the Tibet Autonomous Region. (Photo by Aritz Parra/AP Photo)

Bulgarian Muslims Azim Liumankov and his bride Fikrie Bindzheva pose in front of their house during their wedding ceremony in the village of Ribnovo, in the Rhodope Mountains, February 15, 2015. The remote mountain village of Ribnovo in southwest Bulgaria has kept its traditional winter marriage ceremony alive despite decades of Communist persecution, followed by poverty that forced many men to seek work abroad. (Photo by Stoyan Nenov/Reuters)

In this September 10, 1977, file photo, from left, Hua Guofeng, Chinese Communist Party (CCP) chairman and Mao Zedong's immediate successor; Ye Jianying, CCP vice chairman and future ceremonial head of state; Deng Xiaoping, no formal titles at the time but soon to emerge as paramount leader during the reform era; Li Xiannian, CCP vice chairman and future president; Wang Dongxing, head of the leadership bodyguard unit who helped topple the Gang of Four, view the body of later Chinese leader Mao Zedong in Beijing. (Photo via AP Photo)

A student falls asleep as she holds a book containing a portrait of China's late chairman Mao Zedong during a lesson at the Democracy Elementary and Middle School in Sitong town, Henan province December 3, 2013. In a remote part of central China, the day starts at the Democracy Elementary and Middle School with a pre-dawn jog, some revolutionary songs and then an activity long since forgotten at other schools: reciting quotations from Mao Zedong's famed “Little Red Book”. While the ruling Communist Party that Mao led continues to hold him in esteem as the leader of the Communist Revolution, his radical policies and teachings have been largely shelved since his death in 1976 in favour of a pro-market approach that has turned China from a backwater into the world's second biggest economy. The 120th anniversary of Mao's birth is on December 26, 2013. (Photo by Carlos Barria/Reuters)