Opera singers perform in the pool “AquAria PALAOA” during a rehearsal at the swimming pool Neukoelln on April 27, 2011 in Berlin, Germany. The premiere of the underwater opera AquAria PALAOA is on May 1st. (Photo by Andreas Rentz/Getty Images)

Street fighting in Berlin between Government troops and Spartacists, during the Spartacist uprising which followed Germany's defeat in World War I. (Photo by Keystone/Getty Images). 1919

Egyptian President Hosni Mubarak speaks to the media after talks with German Chancellor Angela Merkel at the Chancellery on April 23, 2008 in Berlin, Germany. (Photo by Sean Gallup/Getty Images)

Keith Richards, Mick Jagger, Ron Wood of the Rolling Stones perform during their "14 on Fire" show at Waldbuehne in Berlin, June 10, 2014. REUTERS/Thomas Peter

Dancers wait backstage during a dress rehearsal for the new “THE ONE Grand Show” at Friedrichstadt-Palast in Berlin, Germany, September 21, 2016. From silver body suits with giant mohawks to revealing fishnet tops with huge feathers, colourful, extravagant costumes take centre stage at a new theatrical show in Berlin. French couturier Jean Paul Gaultier has swapped the Paris runway for the German stage to create some 500 costumes for “THE ONE Grand Show”, an 11-million euro ($12.2 million) production showcasing plenty of singing, dancing and acrobatics. (Photo by Hannibal Hanschke/Reuters)

A dog, at the behest of his owner, rides a skatebaord on April 3, 2017 in Berlin, Germany. The dog's owner, who looked like he might be homeless, coaxed the dog to ride the skatebaord and asked passersby who stopped to watch for money. (Photo by Sean Gallup/Getty Images)

A car “crashed” into the ground at Hackescher Markt in Berlin, Germany on November 15, 2016, ahead of the launch of Jeremy Clarkson, Richard Hammond and James May's new show, “The Grand Tour”, on Amazon Prime Video, on Friday. (Photo by Clemens Bilan/Getty Images for Amazon Prime Video)

A mural painting by graffiti artist Eme Freethinker features likenesses of US President Donald Trump (R) and Chinese premier Xi Jinping wearing face covers in Berlin on April 28, 2020 amid the new coronavirus COVID-19 pandemic. (Photo by John Macdougall/AFP Photo)