Before President Obama delivers his farewell address to the nation tonight, take a look back at some of his most memorable speeches — from his keynote during the 2004 Democratic National Convention to his 2012 election victory speech. More on Obama's legacy: http://nbcnews.to/2iRPwUV | NBC News

He says it's "a speech that changed the United States." Barack Obama's keynote address at the 2004 Democratic National Convention was the topic of a class taught by Univ. of Kansas political communication professor Robert Rowland. Watch "Lectures in History: Obama's 2004 DNC Keynote Address," 10/7 at 8pm ET on C-SPAN 2: https://www.c-span.org/video/?529961-2/obamas-2004-dnc-keynote-adress | American History TV

Words have the power to rally humanity to do great and terrible things. Here, we look at examples of speeches throughout history that showed us at our best...and at our worst. | Timeline - World History