Civil rights icon John Lewis was mourned, revered and celebrated as an American hero on Thursday when he was finally laid to rest at a historic Atlanta cemetery that was a burial site of former slaves and their children. Lewis died July 17 at the age of 80. Three former US presidents - George Bush, Bill Clinton and Barack Obama - joined in the eulogies where Obama described Lewis as "a man of pure joy and unbreakable perseverance". Hundreds gathered to watch the service on a large screen outside the church. Some sang the gospel song "We Shall Overcome."