Link to the relevant section of Obama's "A World that Stands as One" speech in Berlin on 24th July 2008...

...which begins:

"Sixty years after the airlift, we are called upon again. History has led us to a new crossroad, with new promise and new peril. When you, the German people, tore down that wall -- a wall that divided East and West; freedom and tyranny; fear and hope -- walls came tumbling down around the world. From Kiev to Cape Town, prison camps were closed, and the doors of democracy were opened. Markets opened too, and the spread of information and technology reduced barriers to opportunity and prosperity. While the 20th century taught us that we share a common destiny, the 21st has revealed a world more intertwined than at any time in human history."