The Tribute in Light, as seen from across the Hudson River, on the 16th anniversary of the Sept. 11 terror attacks, Monday, Sept. 11, 2017, in Jersey City (AP Photo/Jason DeCrow)
The Tribute in Light is seen in the sky above Lower Manhattan on the 16th anniversary of the Sept. 11 terror attacks, Monday, Sept. 11, 2017, in New York. (AP Photo/Jason DeCrow)
A couple embraces as the Tribute in Light is seen in the sky on the 16th anniversary of the Sept. 11 terror attacks, Monday, Sept. 11, 2017, in New York. (AP Photo/Jason DeCrow)
A couple embraces on the Brooklyn Promenade as the Tribute in Light rises above the lower Manhattan skyline Sunday, Sept. 10, 2017, in New York. (AP Photo/Mark Lennihan)
The Tribute in Light rises above the lower Manhattan skyline, Sunday, Sept. 10, 2017, in New York. (AP Photo/Mark Lennihan)
The Tribute in Light, a temporary memorial to those lost on 9/11, is lit for the last time on Saturday, April 13, 2002. It was on continuously for six months after the attack. (AP Photo/ JOHN-MARSHALL MANTEL)
New York Firefighters Tim Hallahan, left, and Lt. Peter White look at "Tribute in Light," Saturday, April 13, 2002. (AP Photo/ JOHN-MARSHALL MANTEL)
The Tribute in Light rises above the New York skyline, Friday, Sept. 11, 2015 in a view from Bayonne, N.J. (AP Photo/Mark Lennihan) (AP Photo/ Mark Lennihan)
The Tribute in Light rises above the New York skyline Friday, Sept. 11, 2015. (AP Photo/ Mark Lennihan)
The Tribute in Light rises above the New York skyline Friday, Sept. 11, 2015, in a view from Bayonne, N.J. (AP Photo/ Mark Lennihan)
The "Tribute in Light" towers above lower Manhattan during the second anniversary of the Sept. 11 terrorists attacks Thursday, Sept. 11, 2003. (AP Photo/ DANIEL P. DERELLA)
Jose Martinez, left, and his brother Adonis Martinez, of Danbury, Conn., pose for a friend's snapshot below The Tribute in Light near Ground Zero on Friday, Sept. 12, 2003. (AP Photo/ JOHN MARSHALL MANTEL)
The Tribute in Light, a temporary memorial to those lost on 9/11, is lit for the last time on Saturday, April 13, 2002. It was on continuously for six months after the attack. (AP Photo/ JOHN-MARSHALL MANTEL)
The Tribute in Light rises near Ground Zero on Sept. 12, 2003. The twin beams of light were switched on at sunset, evoking the image of the twin towers. (AP Photo/ JOHN MARSHALL MANTEL)
A test of the Tribute in Light memorial illuminates a passing cloud above lower Manhattan Thursday, Sept. 9, 2004, in New York. (AP Photo/ MIKE HVOZDA)
In this Sept. 11, 2004 file photo, the Tribute in Light shines over the Manhattan skyline and the Statue of Liberty in New York. (AP Photo/ Brian Branch-Price)
'Tribute in Light' illuminates the sky over Manhattan, Monday, Sept. 11, 2006 in New York, marking the fifth anniversary of the Sept. 11 terror attacks. (AP Photo/ DIMA GAVRYSH)
The "Tribute in Light" marks the September 11 Anniversary in New York taken from Bayonne, N.J. on Tuesday, Sept. 11, 2007. (AP Photo/ Tim Larsen)
A short test of the "Tribute in Light" illuminates the sky over the World Trade Center site Wednesday, Sept. 10, 2008 in New York. (AP Photo/ Mark Lennihan)
The Tribute in Light illuminates the sky over the Brooklyn Bridge and lower Manhattan Thursday, Sept. 11, 2008 in New York. (AP Photo/ Mark Lennihan)
Twin towers of light from the Tribute in Light converge over the spire of Trinity Church in Lower Manhattan in New York, Thursday, Sept. 11, 2008. (AP Photo/ Kathy Willens)
In a photo made with a fisheye lens, the Tribute in Light rises above buildings in lower Manhattan, during a test, Tuesday, Sept. 10, 2013. (AP Photo/ Mark Lennihan)
The Tribute in Light rises above the construction cranes on One World Trade Center, and the lower New York skyline, Saturday, Sept. 11, 2010.. (AP Photo/ Mark Lennihan)
The Tribute in Light rises above the construction cranes on One World Trade Center, and the lower New York skyline, Saturday, Sept. 11, 2010. (AP Photo/ Mark Lennihan)
A test of the Tribute in Light rises above lower Manhattan, Wednesday, Sept. 7, 2011 in New York. (AP Photo/ Seth Wenig)
The Tribute in Light rises above the lower Manhattan skyline and One World Trade Center, center, in a test of the memorial light display, Monday, Sept. 9, 2013 in New York. (AP Photo/ Mark Lennihan)
In this Friday, Sept. 6, 2013 photo, people in Brooklyn Bridge Park gather to watch a test of the Tribute in Light rising from the lower Manhattan skyline in New York. (AP Photo/ Mark Lennihan)
The Tribute in Light shines above the World Trade Center and the Statue of Liberty, left, Monday, Sept. 10, 2012, as seen from Bayonne, N.J. (AP Photo/ Mark Lennihan)
A test of the twin beams of the Tribute in Light intersect with still-under construction One World Trade as they rise above lower Manhattan, Monday, Sept. 9, 2013. (AP Photo/ Kathy Willens)
The Tribute in Light shines above 1 World Trade Center, left, and 7 World Trade Center, Tuesday, Sept. 11, 2012 in New York. (AP Photo/ Mark Lennihan)
A test of the Tribute in Light shines skyward over lower Manhattan, Friday, Sept. 7, 2012 in New York. (AP Photo/ Mark Lennihan)