A moment of silence is held Saturday at the National September 11 Memorial and Museum in New York. From left are former President Bill Clinton; former first lady and US Sen. Hillary Clinton; former President Barack Obama; former first lady Michelle Obama; President Joe Biden; first lady Jill Biden; former New York City Mayor Michael Bloomberg; Bloomberg's partner, Diana Taylor; and House Speaker Nancy Pelosi.
Chip Somodevilla/Pool/AFP/Getty Images

The week in 40 photos

Updated 7:41 PM ET, Thu September 16, 2021

A moment of silence is held Saturday at the National September 11 Memorial and Museum in New York. From left are former President Bill Clinton; former first lady and US Sen. Hillary Clinton; former President Barack Obama; former first lady Michelle Obama; President Joe Biden; first lady Jill Biden; former New York City Mayor Michael Bloomberg; Bloomberg's partner, Diana Taylor; and House Speaker Nancy Pelosi.
Chip Somodevilla/Pool/AFP/Getty Images

The past week marked a somber milestone in the United States as we stopped to remember those killed in the September 11 terrorist attacks 20 years ago.

Memorial services were held in New York, Pennsylvania and Virginia, and President Joe Biden visited all three sites. In New York, he was joined by former Presidents Bill Clinton and Barack Obama.

"These memorials are really important," Biden said during his stop in Pennsylvania. "But they're also incredibly difficult for the people affected by them, because it brings back the moment they got the phone call, it brings back the instant they got the news, no matter how years go by."

Take a look at more photos from that day and other major news stories from September 10 to September 16.