Now some 75 years later, the Presidents of Poland and Germany stand side by side. In the shadows of the Russian-Ukrainian conflict, Polish President, Bronislaw Komorowski, speaks of learning from the past.
"History gives a lesson," he says. "It gives a lesson and it compels to draw conclusions from painful experiences, history tells us that there is still need for courage and determination in defying those who threaten the international order, peace and freedom. That there is still need for efforts for reconciliation and integration. That we need to support those who aim towards a world where a neighbour does not need to be afraid of their neighbour."
Polish forces were overwhelmed by German superiority in numbers and firepower. Among the German staff watching the siege of the capital was Adolph Hitler himself who had flown in from Berlin.
After Russia annexed Crimea, amid fears of Moscow's ambitions in Ukraine German President Joachim Gauck issues a warning:
"We will oppose those who break international law, annex foreign territory and give military support for the separation of other countries. That is why we stand by those values to which we owe our free and peaceful coexistence. We will adjust our politics, economy and the preparedness to adjust to the new circumstances."
The Second World War lasted nearly six years. More than 45 million people perished, with some putting the death toll as high as 60 million.