Ceremonies mark 17th anniversary of 9/11 attacks(42 images)

A boy with the name of a 9/11 victim on the back of his shirt arranges a flower at the reflecting pools at the 9/11 Memorial near One World Trade Center at Ground Zero in New York City. Robert Houghes, the victim on the boy's shirt, was 23 years old. Houghes, a margins clerk at Bank of America, assisted an elderly woman down the stairs from the 83rd floor when the plane hit the tower. He was last seen by co-workers on the bottom floor of the towers before debris started coming down. Photo by John Angelillo/UPI

An American flag and a banner are placed at the reflecting pools. Photo by John Angelillo/UPI

An American flag is unfurled on the side of the Pentagon at the location of the Sept. 11, 2001, terrorist attack in Arlington, Va. Photo by Kevin Dietsch/UPI

Vice President Mike Pence delivers remarks at the the 17th anniversary memorial service for the 9/11 terrorist attacks, at the National 9/11 Pentagon Memorial, at the Pentagon, in Arlington, Va. Photo by Kevin Dietsch/UPI

A flower is seen on a bench at the National 9/11 Pentagon Memorial. Photo by Kevin Dietsch/UPI

Vice President Mike Pence, his wife Karen Pence, Defense Secretary James Mattis (R) and Vice Chairman of the Joint Chiefs of Staff Air Force Gen. Paul J. Selva, lay a wreath the the National 9/11 Pentagon Memorial. Photo by Kevin Dietsch/UPI

Family members arrive for the 17th anniversary memorial service for the 9/11 terrorist attacks, at the National 9/11 Pentagon Memorial. Photo by Kevin Dietsch/UPI