Each August and September, as summer fades into fall, Yahoo News photographer Gordon Donovan finds himself in a familiar spot — snapping images in the area where the 9/11 terrorist attacks took place.

“I do it because I love the city, the history of the city and how we’re not going to be put down,” explained Donovan, who was born and raised on Staten Island and watched the twin towers being built from across the harbor.

But his photos aren’t random shots of the evolving downtown landscape. He returns to document the exact scenes of many memorable images taken by photojournalists that awful day in 2001.

“It’s fascinating to see how it has changed over the years, because it was just this big pile of rubble the first time I went down there, about a week afterward,” said Donovan, then a graphic artist at CBS News, who was at work on the Upper West Side the morning of the attack.

Today a memorial and museum honor the nearly 3,000 people killed. The area also includes a recently opened transportation hub, and there are other signs of development yet to come.

“Now you can’t even recognize what happened,” Donovan said. “What they’ve done down there is beautiful and just revitalized the whole area after such tragedy and brought it back to life.”

Donovan’s then-and-now project, he said, is a testament to the city’s strength and an opportunity to share the changes with New Yorkers who may have moved away over the past 18 years. He said his project also honors the photojournalists who took the original images on 9/11.

New obstacles have arisen, requiring some adjustments in camera angles to align with the original images. This is the eighth time Donovan has revisited the New York skyline to document changes since 9/11; each year presents new challenges as the New York City landscape changes.

Drag the slider across each pair of images to see changes in the New York City landscape.

Looking downtown from the ‘Top of the Rock’

2001: The twin towers of the World Trade Center burn behind the Empire State Building, Sept. 11, 2001. (Photo: Marty Lederhandler/AP)

 

2019: One World Trade Center towers above the landscape in lower Manhattan behind the Empire State Building, Sept. 5, 2019. (Photo: Gordon Donovan/Yahoo News)

Across the East River in Brooklyn

2001: Pedestrians on the waterfront in Brooklyn look across the East River to the burning World Trade Center towers on Sept. 11, 2001. (Photo: Henny Ray Abrams/AFP/Getty Images)
2019: People take photographs of the New York City skyline from Pier 1 at Brooklyn Bridge Park on Sept. 5, 2019. (Photo: Gordon Donovan/Yahoo News)

Steeple at Trinity Church

2001: Smoke spews from a tower of the World Trade Center on Sept. 11, 2001, after two hijacked airplanes hit the twin towers in a terrorist attack on New York City. (Photo: Mario Tama/Getty Images)

2019: Before 9/11, the original World Trade Center towers could be seen from the Trinity Church Cemetery in lower Manhattan, Sept. 2, 2019. (Photo: Gordon Donovan/Yahoo News)

World Trade Center survivors covered in dust

2001: People struggle through debris near the World Trade Center on Sept. 11, 2001. (Photo: Gulnara Samoilova/AP)

 

2019: Pedestrians make their way along Fulton Street next to St. Paul’s Chapel of Trinity Church on Sept. 2, 2019. (Photo: Gordon Donovan/Yahoo News)

Across the Brooklyn Bridge

2001: Women wearing dust masks flee from Manhattan to Brooklyn on the Brooklyn Bridge following the collapse of both World Trade Center towers, Sept. 11, 2001. (Photo: Mark Lennihan/AP)

 

2019: People head toward Brooklyn from Manhattan across the Brooklyn Bridge, Sept. 5, 2019. (Photo: Gordon Donovan/Yahoo News)

Subway on Cortlandt Street

2001: A destroyed subway station near Ground Zero on the evening of Sept. 12, 2001, after the Sept. 11 terrorist attacks on the World Trade Center. (Photo: Mark Lennihan/AP)

 

2019: Traffic along Church Street passes the Cortlandt Street subway station on Sept. 3, 2019, across the street from Three World Trade Center. (Photo: Gordon Donovan/Yahoo News)

Vesey Street covered in debris

2001: A firefighter walks amid the rubble near the base of the destroyed World Trade Center on Sept. 11, 2001. (Photo: Peter Morgan/Reuters)

 

2019: Commuters head to work on Vesey Street near the World Trade Center on Sept. 2, 2019. (Photo: Gordon Donovan/Yahoo News)

Covered in dust from collapse of towers

2001: Pedestrians on Beekman Street flee the area of the collapsed World Trade Center in lower Manhattan following the terrorist attack, Sept. 11, 2001. (Photo: Amy Sancetta/AP)

 

2019: A man walks past a parking garage on Beekman Street on Sept. 5, 2019. (Photo: Gordon Donovan/Yahoo News)

The South Tower

2001: Remains of the facade of Two World Trade Center are all that stands on the World Trade Center site, Sept. 12, 2001. (Photo: AP)

2019: Visitors gather to pay tribute to the victims of the 9/11 attacks near one of two reflecting pools at the National September 11 Memorial & Museum, Sept. 4, 2019. (Photo: Gordon Donovan/Yahoo News)

WTC Cortlandt Street subway

2001: Debris covers the Vesey Street entrance to the Cortlandt Street stop of the No. 1 and No. 9 subway lines under the World Trade Center, in this undated photo made available Sept. 28, 2001. (Photo: New York City Transit/AP)
2019: The downtown entrance of the WTC Cortlandt Subway No. 1 station that reopened in 2018, Sept. 7, 2019. (Photo: Gordon Donovan/Yahoo News)

The Sphere at the World Trade Center

2001: Fritz Koenig’s “The Sphere,” a 25-ton sculpture that once graced the plaza at the World Trade Center, lies in the wreckage following the Sept. 11, 2001, terrorist attack. (Photo: Shawn Baldwin/AP)

 

2019: “The Sphere” has been relocated to Liberty Park, which overlooks the World Trade Center memorial, Sept. 2, 2019. (Photo: Gordon Donovan/Yahoo News)

Fire truck covered in debris

2001: A fire truck is surrounded by dust and debris near the site of the terrorist attack on the World Trade Center, Sept. 11, 2001. (Photo: Bernadette Tuazon/AP)
2019: Eighteen years after the collapse of the World Trade Center towers, construction continues on Greenwich and Rector Streets, Sept. 2, 2019. (Photo: Gordon Donovan/Yahoo News)

World Trade Center skeleton

2001: The remains of the World Trade Center stand amid the debris following the terrorist attack, Sept. 11, 2001. (Photo: Alexandre Fuchs/AP)
2019: The World Trade Center buildings and the National September 11 Memorial & Museum seen from West Street, Sept. 2, 2019. (Photo: Gordon Donovan/Yahoo News)

Brooks Brothers covered in rubble

2001: A destroyed Brooks Brothers store near Ground Zero on Sept. 11, 2001 after the terrorist attack. (Photo: Mark Lennihan/AP)

 

2019: People walk past the now closed Brooks Brothers store on Church Street, Sept. 3, 2019. (Photo: Gordon Donovan/Yahoo News)

Firemen on Cortlandt Street

2001: With the skeleton of the World Trade Center twin towers in the background, New York City firefighters work amid debris on Cortlandt Street after the terrorist attacks in this photo taken Sept. 11, 2001. (Photo: Mark Lennihan/AP)

 

2019: People walk down Cortlandt Street toward the World Trade Center on Sept. 3, 2019. (Photo: Gordon Donovan/Yahoo News)

McDonald’s closed on Broadway

2001: A street near Ground Zero on the evening of Sept. 11, 2001, after the terrorist attacks on the World Trade Center. (AP Photo/Mark Lennihan)
2019: Businesses such as McDonald’s are open on lower Broadway on Sept. 4, 2019, as construction continues near the World Trade Center site. (Photo: Gordon Donovan/Yahoo News)

Facade on Church Street

2001: Parts of the facade of the World Trade Center after the terrorist attack, Sept. 12, 2001. (Photo: Nick Fanelli/AP)