Photos of 9/11: Attacks, aftermath, memorials and remembrance

FILE - Women wearing dust masks flee across the Brooklyn Bridge from Manhattan to Brooklyn following the collapse of both World Trade Center towers Tuesday, Sept. 11, 2001 in New York. The towers previously loomed tall in the skyline behind.

FILE - In this Sept. 11, 2001 file photo the twin towers of the World Trade Center burn behind the Empire State Building in New York after terrorists crashed two planes into the towers, causing both to collapse.

FILE- In this Sept. 11, 2001 file photo, smoke billows from World Trade Center Tower 1 and flames explode from Tower 2 as it is struck by American Airlines Flight 175, in New York.

FILE - In this Sept. 24, 2001 file photo, Fritz Koenig’s “The Sphere” outdoor sculpture that once graced the plaza at New York’s World Trade Center lies in the wreckage following the Sept. 11, 2001, terrorist attacks.

FILE - Smoke billows from one of the towers of the World Trade Center and flames and debris explode from the second tower, Tuesday, Sept. 11, 2001. In one of the most horrifying attacks ever against the United States, terrorists crashed two airliners into the World Trade Center in a deadly series of blows that brought down the twin 110-story towers.

FILE - A jet crashes into the World Trade Center in New York, Tuesday, Sept. 11, 2001.

FILE - Visitors are shown at the Texas 9/11 Memorial before dedication ceremonies in the State Cemetery, Thursday, Sept. 11, 2003, in Austin, Texas. The memorial stands in honor of those Texans who perished in the attacks of Sept. 11, 2001, and those serving in Operaton Enduring Freedom. The memorial includes two mangled steel beams from the World Trade Center.

FILE - This Sunday, Sept. 11, 2005 file photo shows the “Memory and Light” monument designed by Daniel Libeskind, the architect who created the master plan for reconstruction at ground zero, in Padua, northern Italy. Italy marked the fourth anniversary of the 9/11 attacks with a new glass and steel memorial monument that incorporates a twisted steel beam from the World Trade Center.

FILE - In this photograph provided by America Supports You, the Pennsylvania National Guard Color Guard leads the procession of The America Supports You National Freedom Walk as it processes South on the George Washington Parkway, Sunday, Sept. 9, 2007, in Washington. The third annual walk started at the Lincoln Memorial and concluded at the Pentagon, It commemorates those lost on 9/11 and honored veterans past and present.

FILE - In this Aug. 25, 2011 photograph, a memorial marker stands in this Durant, Miss., city park honoring the two Durant High School graduates that died in the 9/11 attack at the Pentagon, Joe Ferguson, a 39-year-old National Geographic employee who died aboard the downed airliner and Army Lt. Col. Joe Don “D.D.” Dickerson, who was working inside the military complex.

FILE - In this Aug. 25, 2011 photograph, a memorial marker stands in front of a gazebo in this Durant, Miss., city park honoring the two Durant High School graduates that died in the 9/11 attack at the Pentagon: Joe Ferguson, a 39-year-old National Geographic employee who died aboard the downed airliner and Army Lt. Col. Joe Don “D.D.” Dickerson, who was working inside the military complex.

FILE - Joe Griffith of Beverly Hills, Calif. touches a piece of steel from the World Trade Center on the 10th anniversary of 9/11 at a memorial in Beverly Hills, Calif., Sunday, Sept. 11, 2011.

FILE - Residents inspect a 9/11 memorial featuring a piece of steel from the World Trade Center on the 10th anniversary of 9/11 in Beverly Hills, Calif., Sunday, Sept. 11, 2011.

FILE - Chris Kayder and his daughter, Cadence, walk among the flags honoring those who died in the 9/11 attacks Monday, Sept 10, 2012 at the healing field in Tempe, Ariz. Each flag represents a person who lost his or her life in the attacks on the World Trade Center in New York City, the Pentagon in Washington, D.C., and Pennsylvania in 2001, and are marked with placards with the name of victims, information about them and where they died.

FILE - Flight attendant Shirley Evatt looks at flowers laid at the 9/11 Flight Crew Memorial in Grapevine, Texas, Tuesday, Sept. 11, 2012. Flight crews gathered at the memorial near DFW airport to remember the flight crews lost in the Sept. 11, 2001 terror attacks.

FILE - Afghan President Hamid Karzai, third from right, and Defense Secretary Leon Panetta, right, get a tour of the National 9/11 Pentagon Memorial by James Laychak, president of the Pentagon Memorial Fund, center, Thursday, Jan. 10, 2013, at the Pentagon.

FILE - Shown is the Garden of Reflection memorial to local victims of the 9/11 terrorist attacks, Monday, April 29, 2013, in Yardley, Pa.

FILE - Shown is the Garden of Reflection memorial to local victims of the 9/11 terrorist attacks, Monday, April 29, 2013, in Yardley, Pa.

FILE - Shown is the Garden of Reflection memorial to local victims of the 9/11 terrorist attacks, Monday, April 29, 2013, in Yardley, Pa.

FILE - Shown is the Garden of Reflection memorial to local victims of the 9/11 terrorist attacks, Monday, April 29, 2013, in Yardley, Pa.

FILE - Shown is the Garden of Reflection memorial to local victims of the 9/11 terrorist attacks, Monday, April 29, 2013, in Yardley, Pa.

FILE - In this Sept. 11, 2015 file photo, President Barack Obama, first lady Michelle Obama, and others, pause on the South Lawn of the White House in Washington as they observe a moment of silence to mark the 14th anniversary of the 9/11 attacks.

Olivia Lindhardt volunteers with others to set up 3,000 flags in the Utah Healing Field in Sandy on Thursday, Sept. 8, 2016, to honor the victims of the 9/11 terrorist attacks.

Nikki Moore and other volunteers set up 3,000 flags in the Utah Healing Field in Sandy on Thursday, Sept. 8, 2016, to honor the victims of the 9/11 terrorist attacks.

Volunteers set up 3,000 flags in the Utah Healing Field in Sandy on Thursday, Sept. 8, 2016, to honor the victims of the 9/11 terrorist attacks.

Volunteers set up 3,000 flags in the Utah Healing Field in Sandy on Thursday, Sept. 8, 2016, to honor the victims of the 9/11 terrorist attacks.

Olivia Lindhardt volunteers with others to set up 3,000 flags in the Utah Healing Field in Sandy on Thursday, Sept. 8, 2016, to honor the victims of the 9/11 terrorist attacks.

Cody Brophy volunteers with others to set up 3,000 flags in the Utah Healing Field in Sandy on Thursday, Sept. 8, 2016, to honor the victims of the 9/11 terrorist attacks.

Mechanical, Electrical and Plumbing Superintendent Rick Bandy carries the flag away after Holder and Big-D construction workers on the Salt Lake City International Airport rebuild project held a ceremony to remember the events of 9/11 on Friday, Sept. 9, 2016.

Holder and Big-D construction workers on the Salt Lake City International Airport rebuild project fold the flag after holding a ceremony to remember the events of 9/11 on Friday, Sept. 9, 2016.

Salt Lake City International Airport police salute as the colors are retired as Holder and Big-D construction workers on the airport rebuild project hold a ceremony to remember the events of 9/11 on Friday, Sept. 9, 2016.

Holder and Big-D Construction workers on the Salt Lake City International Airport rebuild project hold a ceremony to remember the events of 9/11 on Friday, Sept. 9, 2016.

Construction workers on the Salt Lake City International Airport rebuild project hold a ceremony to remember the events of 9/11 on Friday, Sept. 9, 2016.

Mechanical, Electrical and Plumbing Superintendent Rick Bandy carries an American flag after Holder and Big-D construction workers on the Salt Lake City International Airport rebuild project held a ceremony to remember the events of 9/11 on Friday, Sept. 9, 2016.

Holder and Big-D construction workers on the Salt Lake City International Airport rebuild project prepare to fold the American flag after holding a ceremony to remember the events of 9/11 on Friday, Sept. 9, 2016.

The morning sun shines brightly through an American flag during a 9/11 remembrance ceremony at Fort Gordon, Ga., Friday, Sept. 9, 2016.

The memorial statue titled, “To the Struggle Against World Terrorism”, by Russian artist Zurab Tsereteli, is seen during dedication ceremonies in Bayonne, N.J., Monday, Sept. 11, 2006. The 100-foot-tall bronze monument with a 40-foot steel teardrop at it’s center is a gift from the Russian government and Tsereteli is dedicated to victims of terrorism.

People gather to view a memorial to the victims of the 1993 and 2001 attacks on the World Trade Center as the sun sets on the esplanade in the Staten Island borough of New York City, Saturday, Sept. 11, 2004. The memorial, titled “Postcards,” was formally dedicated Saturday.

Shown is the Garden of Reflection memorial to local victims of the 9/11 terrorist attacks, Monday, April 29, 2013, in Yardley, Pa.

People walk through the Empty Sky memorial at Liberty State Park, Friday, July 25, 2014, in Jersey City, N.J.

People gather to view a memorial to the victims of the 1993 and 2001 attacks on the World Trade Center on the esplanade in the Staten Island borough of New York Saturday, Sept. 11, 2004 as the “Tribute in Light” shines from lower Manhattan to mark the third anniversary of the terrorist attacks. The memorial, titled “Postcards,” was formally dedicated Saturday.

People gather to view a memorial to the victims of the 1993 and 2001 attacks on the World Trade Center on the esplanade in the Staten Island borough of New York City Saturday, Sept. 11, 2004 as the “Tribute in Light” shines from lower Manhattan to mark the third anniversary of the terrorist attacks. The memorial, titled “Postcards,” was formally dedicated Saturday.

View of the Pentagon’s September 11th memorial at Arlington National Cemetery, Sunday, Sept. 10, 2006, in Arlington, Va.

The Arizona 9-11 Memorial is seen Monday, Sept. 25, 2006 in Phoenix, Ariz. Joined by parents of several military personnel killed in Iraq, Republican gubernatorial candidate Len Munsil on Monday called for replacement of the recently dedicated Arizona 9-11 Memorial because of inscriptions that they said insult America either by words or omission.

Steven Spaltro, of Middletown, N.J., stands with his dog Tyson in front of the Empty Sky Memorial at Liberty State Park, Thursday, Sept. 11, 2014, in Jersey City, N.J. The country is observing the 13th anniversary of the terrorist attacks on the World Trade Center.

Joe Griffith of Beverly Hills, Calif. touches a piece of steel from the World Trade Center on the 10th anniversary of 9/11 at a newly unveiled memorial in Beverly Hills, Calif., Sunday, Sept. 11, 2011.

A group holds flags as they prepare to run while they stand inside the “Empty Sky” memorial to New Jersey’s victims of the Sept. 11, 2001 terrorist attacks, early Friday, Sept. 11, 2015, in Jersey City, N.J.

A visitor reaches to touch a name engraved at the Sept. 11 memorial site to remember the victims of the 2001 attacks on the World Trade Center, Thursday Sept. 8, 2016, in New York. Sunday marks the 15th anniversary of the terror attacks.

Yellow roses are placed over the name of Robert Clinton Kennedy at the World Trade Center Memorial, Friday, Sept. 9, 2016, in New York. Kennedy, a senior vice president at Marsh & McLennan, was on the 100th floor of the North Tower on Sept. 11, 2001, when terrorists flew a plane into the tower. Kennedy, from Toms River, N.J., and 3,000 others were killed in the attacks in the U.S. Sunday marks the 15th anniversary.

Visitors look at the waterfalls at the World Trade Center Memorial, Friday, Sept. 9, 2016, in New York. Sunday marks the 15th anniversary of the terrorist attacks of Sept. 11, 2001.

National September 11 Memorial take a photo through the window of the museum, Saturday, Sept. 10, 2016, in New York. Sunday marks the 15th anniversary of the attacks on the World Trade Center.

American flags are placed on the south pool of the National September 11 Memorial, Saturday, Sept. 10, 2016, in New York. Sunday marks the 15th anniversary of the attacks on the World Trade Center.

Edward Noon, 22, of the Pennsylvania National Guard, pays tribute to the passengers and crew of Flight 93, while candles are lit along the Wall of Names at the Flight 93 National Memorial in Shanksville, Pa, Saturday, Sept. 10, 2016, as the nation marks the 15th anniversary of the Sept. 11 attacks.

Visitors pay tribute to the passengers and crew of Flight 93 on the Wall of Names at the Flight 93 National Memorial in Shanksville, Pa, Saturday, Sept. 10, 2016, as the nation marks the 15th anniversary of the Sept. 11 attacks.

Candles are lit while visitors pay tribute to the passengers and crew of Flight 93 on the Wall of Names at the Flight 93 National Memorial in Shanksville, Pa, Saturday, Sept. 10, 2016, as the nation marks the 15th anniversary of the Sept. 11 attacks.

Visitors make their way through the Flight 93 National Memorial before lit candles are carried to the Wall of Names in memory of the passengers and crew of Flight 93, at the Flight 93 National Memorial in Shanksville, Pa., Saturday, Sept. 10, 2016, as the nation marks the 15th anniversary of the Sept. 11 attacks.