Stakes were high going into Obama's planned speech in Berlin after a near-perfect overseas trip that many have tamped down fears of how Obama would handle U.S. foreign policy.
In advance of the speech, Obama told reporters: "Hopefully it will be viewed as a substantive articulation of the relationship I would like to see between the United States and Europe...I am hoping to communicate across the Atlantic the value of that relationship and how we need to build on that."
Obama flew to Berlin from the Middle East, where he had toured Jerusalem and met with Israeli and Pakistani leaders.
Closing his evening speech before a throng of Europeans who had gathered to see him, Obama said, "People of Berlin -- and people of the world -- the scale of our challenge is great. The road ahead will be long. But I come before you to say that we are heirs to a struggle for freedom. We are a people of improbable hope. Let us build on our common history, and seize our common destiny, and once again engage in that noble struggle to bring justice and peace to our world."
But even as Obama was greeted by enthusiasm overseas, not all were heeding the call at home, where the candidate will face voters in November.
"What has upset me is that he is over there acting presidential ... I don't want him over there representing me," Columbus, Ohio, resident Diane Woods said during McCain's visit.
"I don't know why Obama's getting all this attention," she said, "McCain is right where he should be -- in America."
ABC News' David Wright contributed to this report.