PITTSBURGH, PA - Three of the biggest names in Democratic politics - Hillary Clinton, Bernie Sanders and Elizabeth Warren - will be in Pittsburgh this weekend to speak at the American Federation of Teachers Convention.

The three-day event, which begins Friday at the David L. Lawrence Convention Center, is expected to attract more than 3,000 teachers.

Clinton was the Democratic presidential nominee in 2016 and received more of the popular vote than Donald Trump, who won the Electoral College. Talk in political circles is that she is mulling another bid for the presidency in 2020.