'The best is yet to come': Historic Obama presidency in pictures

US President Barack Obama bid farewell in an emotional speech that was a public meditation on the trials and triumphs, promises kept and promises broken during his eight years in the White House. Obama said he was ending his presidentship inspired by America's "boundless capacity" for reinvention. "The future should be ours," he declared.

Obama addressed a crowd of 20,000 at McCormick Place, the largest convention center in North America and the site of his 2012 campaign victory address.

"Yes, our progress has been uneven. The work of democracy has always been hard, contentious and sometimes bloody. For every two steps forward, it often feels we take one step back," he said.

"We weaken those ties when we allow our political dialogue to become so corrosive that people of good character aren't even willing to enter public service; so coarse with rancor that Americans with whom we disagree are not just misguided, but somehow malevolent," Obama added. "We weaken those ties when we define some of us as more American than others; when we write off the whole system as inevitably corrupt, and blame the leaders we elect without examining our own role in electing them."

Throughout his speech, Obama promised a cheering crowd of supporters that "the best is yet to come." He offered his vision for how to surmount the new challenges, and for the persistent problems that he was unable to overcome. He also offered optimism that others, eventually, will.

By the end of the speech, Obama was seen wiping away tears as the crowd embraced him one last time. When the crowd of thousands chanted "Four more years," he simply smiled and said, "I can't do that."