She mentioned Friday's terrorist attack on the U.S. embassy in Turkey to underscore the threats the country faces.
“I know the world we are trying to help bring into being in the 21st century will have many difficult days,” she said. “But I am more optimistic today than I was when I stood here four years ago. Because I have seen, day after day, the many contributions that our diplomats and development experts are making to help ensure that this century provides the kind of peace, progress and prosperity to not just the United States, but the entire world.”
For more on Clinton's farewell, click here.