Robert Koldewey (born 1855) was the German archaeologist who discovered Babylon in today’s Iraq (and perhaps also parts of the Tower of Babel). He excavated the Babylonian Ishtar Gate, now in the Pergamon Museum in Berlin, acquired legally (in forty boxes) in accordance with a treaty between imperial Germany and the Ottoman Empire, both expired in 1918.
Every Wednesday, migrants, mainly from Syria, visit the Gate. They admire it and some are no doubt proud of it and express their gratitude to Germany for looking after it so well, far away from war and disaster.
It is not always easy to explain to them that the treasure was not stolen but was acquired legally in accordance with a treaty concluded between imperial Germany and the Ottoman Empire. Both expired in 1918.
A good case can be made for the heretical view that the world would be a better place if they had not expired and if another agreement had been concluded between them for the peaceful return of the Ishtar Gate to its original location.
Source (except for the last paragraph): Süddeutsche Zeitung, April 7