Remembering the Fallen: 15th anniversary of September 11th

National September 11 Memorial & Museum, photo courtesy National September 11 Memorial & Museum

New York, NY, September 25, 2001 -- The smouldering skeleton and debris from the collapsed World Trade Center dwarfs rescue workers who continue to make headway in clearing the rubble. Photo by Mike Rieger/ FEMA News Photo

New York, NY, September 25, 2001 -- A firefighter surveys the remaining shell and tons of debris of the World Trade Center. Clearing the rubble from the collapsed twin towers and other surrounding buildings is a daunting task for the hundreds of workers at the site of the terrorist attack. Photo by Mike Rieger/ FEMA News Photo

New York, NY, September 25, 2001 -- Fragments of the World Trade Center facade are all that remain of the 110-story structures that once dominated the skyline of lower Manhattan. Photo by Mike Rieger/ FEMA News Photo

New York City skyline on the afternoon of Sept. 11, 2001. (U.S. Air Force photo by Tech. Sgt. Mark C. Olsen, 177th Fighter Wing Public Affairs)

Photos taken at various locations around Ground Zero, formerly the World Trade Center, New York City, N.Y. Sept. 14, 2001. (U.S. Air Force photo by Tech. Sgt. Mark C. Olsen, 177th Fighter Wing Public Affairs)

New York, NY, September 25, 2001 -- The smoldering skeleton and debris from the collapsed World Trade Center dwarfs rescue workers who continue to make headway in clearing the rubble. Photo by Mike Rieger/ FEMA News Photo

New York, NY, September 25, 2001 -- One of the remaining standing fascades at the World Trade Center was brought down this evening. Photo by Andrea Booher/ FEMA News Photo

A memorial flag is illuminated near the spot where American Airlines Flight 77 crashed into the Pentagon on Sept. 11, 2001 in Washington, D.C., Sept. 11, 2007. Photo U.S. Navy MC1(SW) Brandan W. Schulze

Lights begin to illuminate the National 9/11 Pentagon Memorial as the sun sets in Arlington, Va., Sept. 10, 2014. The Pentagon Memorial was created to remember and honor those lost at the Pentagon Sept. 11, 2001. (U.S. Coast Guard photo by Petty Officer 2nd Class Patrick Kelley.)

A bench along the Memorial Plaza Walkway leading to the white marble Wall of Names at the Flight 93 National Memorial. To the left is the Crash Site. Photo by James Steakley

Days after the attacks, the towers of the World Trade Center (WTC) sit as a pile of rubble in the streets of New York City. DoD photo by Staff Sgt. Michelle Leonard, USAF

A Vermont Air National Guard F-16 patrols the skies over New York City on Sept. 12, 2001, in support of Operation Noble Eagle, as the remains of the World Trade Center still burn below. U.S. Air Force photo by Lt. Col. Terry Moultrup

An aerial view, two days later, of the impact point on the Pentagon where the hijacked American Airlines Flight 77, a Boeing 757-200 entered, breaking up in the process. The flag visible to the right of the damaged area is a garrison flag sent from the U.S. Army Band at nearby Fort Myer, Va. DoD photo by Tech Sgt. Cedric H. Rudisill, USAF

Days after the terrorist attacks on American soil, the towers of the World Trade Center (WTC) sit as a pile of rubble in the streets of New York City as rescue and recovery efforts continue. The view is to the south, World Financial Center (WFC) tower 1 in the upper right corner. Visible also is the bridge connecting the WTC and WFC. DoD photo by Staff Sgt. Michelle Leonard, USAF