Returning to Baghdad 20 years since the U.S.-led invasion of Iraq

It's been 20 years since the U.S.-led invasion of Iraq. CBS News' Charlie D'Agata returns to Baghdad, where he was when the series of airstrikes known as "Shock and Awe" launched President George W. Bush's Operation Iraqi Freedom in the early hours of March 20. D'Agata speaks with U.S. Ambassador to Iraq Alina Romanowski who insists Iraq has turned a corner, and with the top U.S. general in charge of the 2,500 Americans who remain in the country. Nearly 4,500 American service members lost their lives by the time of the 2011 withdrawal.