Photo taken in Arlington, Virginia, the United States on Aug. 20, 2020 shows screens displaying images of former U.S. Vice President Joe Biden speaking in a video feed of the 2020 Democratic National Convention. Joe Biden on Thursday formally accepted the Democratic presidential nomination, laying out his vision for building the nation back better in a speech that capped off the four-day virtual Democratic National Convention. (Xinhua/Liu Jie)

WASHINGTON, Aug. 20 -- Former U.S. Vice President Joe Biden on Thursday formally accepted the Democratic presidential nomination, laying out his vision for building the nation back better in a speech that capped off the four-day virtual Democratic National Convention.