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

In the middle of the lobby of the Radisson SAS Hotel in Berlin stands a AquaDom standing 25 meters tall and is the largest cylindrical aquarium ever built. It’s filled with about 900,000 liters of seawater and has 2600 fish of 56 species.

Raising a flag over the Reichstag is a historic World War II photograph taken during the Battle of Berlin on 2 May 1945, by Yevgeny Khaldei.

Snake woman Lunga performs on stage during the “Das Goldene Lenkrad” (“The Golden Steering Wheel”) award ceremony on November 5, 2008 in Berlin, Germany. (Photo by Andreas Rentz/Getty Images)

A man smashes an apple with a sword placed on the head of a man wearing a knave costume during the Easter knight event on April 21, 2014 in Berlin. The easter knight event delivers an insight into medieval lifestyle. (Photo by Rainer Jensen/AFP Photo/DPA)

A mechanic assembles a BMW C evolution electric maxi-scooter at the BMW Berlin motorcycle plant February 23, 2015. The storage capacity of the BMW C evolution's high-voltage 8 kWh battery provides a range of up to 100 kilometres and a maximum speed of 120 km/h. (Photo by Fabrizio Bensch/Reuters)