9/11 anniversary September 11, 2021 10:49 am US Marks 20 Years Since 9/11 Terror Attacks The U.S. marked 20 years since the terror attacks of 9/11 at ceremonies across the country. US & World Videos 1:36 WATCH: Some of the most talked about looks at the Met Gala 3:15 NSC reviewing cease-fire proposal: ‘I don't know that it gets any more sensitive than it is right now' 2:23 Climate change is moving Tornado Alley and driving more tornado outbreaks 1:47 Reese Witherspoon and Ryan Phillippe's daughter Ava calls out body shamers 1:41 Trump fined additional $1,000 for gag order violation and threatened with jail