Heavy smoke from wildfires is darkening skies from the US Midwest to the East Coast, in photos

Heavy, pungent wildfire smoke darkened skies in the U.S. on Thursday from the Great Lakes to parts of the East Coast, reducing visibility and prompting warnings that breathing the air outside could be dangerous.

This is a photo gallery curated by AP photo editors.

Light reflects off the water as the sun sets through wildfire smoke over Edmonton, Alberta, Friday, July 17, 2026. (AP Photo/Andy Bao)

The Sun has an orange cast from smoke coming down from the Canadian wildfires as it sets near the Philadelphia Phillies scoreboard during the fourth inning of a baseball game against the New York Mets, Thursday, July 16, 2026, in Philadelphia. (AP Photo/Chris Szagola)

A watercraft sits in the Detroit River near the skyline during poor air quality due to smoke from Canadian wildfires Thursday, July 16, 2026, in Detroit. (AP Photo/Paul Sancya)

Michael Lesperance weeds his driveway wearing a mask during poor air quality due to smoke from Canadian wildfires Thursday, July 16, 2026, in Grosse Pointe Park, Mich.. (AP Photo/Paul Sancya)

The New York City skyline is seen through a cover of wildfire smoke, in Jersey City, N.J., Friday, July 17, 2026. (AP Photo/Ryan Murphy)

The Jersey City skyline is seen through a cover of wildfire smoke, in Jersey City, N.J., Friday, July 17, 2026. (AP Photo/Ryan Murphy)

The sun is obscured by wildfire smoke as people run in front of the Washington Monument and Lincoln Memorial Reflecting Pool, Friday, July 17, 2026, on the National Mall in Washington. (AP Photo/Julia Demaree Nikhinson)

The sun is obscured by wildfire smoke as it rises behind the Marine Corps War Memorial, Friday, July 17, 2026, in Arlington, Va. (AP Photo/Julia Demaree Nikhinson)

The Statue of Liberty stands during sunset as smoke from wildfires blankets the sky, Thursday, July 16, 2026, in the Brooklyn borough of New York. (AP Photo/Yuki Iwamura)

National Guardsmen patrol the Lincoln Memorial as the sun, obscured by wildfire smoke, rises above the Washington Monument and the Reflecting Pool, Friday, July 17, 2026, on the National Mall in Washington. (AP Photo/Julia Demaree Nikhinson)

A child looks out from the observation deck of the CN Tower as smoke from wildfires in Northwestern Ontario blankets the city of Toronto, Thursday, July 16, 2026. (Cole Burston/The Canadian Press via AP)

A person wearing a mask takes the Staten Island Ferry as as smoke from wildfires blankets the sky, Thursday, July 16, 2026, in New York. (AP Photo/Yuki Iwamura)

The New York City skyline is shrouded in smoke as a flag flies in a park in Weehawken, N.J., Thursday, July 16, 2026. (AP Photo/Seth Wenig)

People take the Staten Island Ferry as smoke from wildfires blankets the sky, Thursday, July 16, 2026, in New York. (AP Photo/Yuki Iwamura)

Wildfire smoke blankets Vandercook Lake as a fisherman tries his luck on Thursday, July 16, 2026, near Jackson, Mich., Thursday, July 16, 2026. (J. Scott Park/Jackson Citizen Patriot via AP)

A person wearing a mask cycles in Times Square as smoke from wildfires blankets the sky, Thursday, July 16, 2026, in New York. (AP Photo/Yuki Iwamura)

The Detroit city skyline is obscured during poor air quality due to smoke from Canadian wildfires Thursday, July 16, 2026, in Detroit. (AP Photo/Paul Sancya)

Hazy skies from Canadian wildfires cover Silver Beach and Lake Michigan, Thursday, July 16, 2026, in St. Joseph, Mich. (Don Campbell/The Herald-Palladium via AP)

A person uses binoculars to look out as smoke from wildfires blankets the sky at Top of The Rock observation deck at the Rockefeller Center, Thursday, July 16, 2026, in New York. (AP Photo/Yuki Iwamura)

A golfer checks his score card at Willow Hills Golf course during poor air quality due to dense smoke from Canadian wildfires in Northbrook, Ill., Thursday, July 16, 2026. (AP Photo/Nam Y. Huh)

A person looks out a window at the Top of the Rock Observation Deck as wildfire smoke hangs over New York, Thursday, July 16, 2026. (AP Photo/Yuki Iwamura)

The Statue of Liberty is photographed from the Staten Island Ferry as smoke from wildfires blankets the sky, Thursday, July 16, 2026, in New York. (AP Photo/Yuki Iwamura)

NEW YORK (AP) — Americans are commemorating the 25th anniversary of 9/11, remembering the shock, the dead and the sweeping consequences of the al-Qaida attacks on symbols of U.S. might and prosperity.

Friday's milestone anniversary will bring memorial rituals — wreath-laying, flag-flying, moments of silence, vigils and readings of victims' names — and volunteer projects in tribute to a day that about half of U.S. adults remember as the most historic event of their lifetime, according to a new poll.

For others it's an occasion for private reflection — or, in many schools, education — about the attack that unfolded in a single morning but left nearly 3,000 dead and a decades-long trail of aftermath, from personal grief to far-flung wars.

Police Officer Casey Kloepfer plans to spend time Friday at the Brooklyn station house where his father, Officer Ronald Kloepfer, reported to work that day before being called to the World Trade Center. He didn't make it home.

Casey Kloepfer was only 4, but he grew up hearing about his father's affinity for helping people and for a job that enabled him to do so. He became an officer this past June.

“It’s big footsteps to fill, but it’s definitely something that I take very seriously and want to continue to honor him and be the best police officer I can,” he said by phone this week. The 29-year-old wears his father’s badge number and even has joined the New York Police Department lacrosse team, which his dad founded.

On Sept. 11, 2001, al-Qaida extremists hijacked four commercial jets and crashed them into New York's World Trade Center, the Pentagon and a field near Shanksville, Pennsylvania.

The impacts brought down the World Trade Center's twin towers — icons of U.S. economic power, and among the tallest buildings on Earth — and blew a hole in the Pentagon, the U.S. military's fortresslike headquarters near Washington. The fourth plane also was headed for the nation's capital, officials concluded, but the aircraft went down in Pennsylvania after passengers and crew members stormed the cockpit and fought the hijackers.

“In the course of history, there are a few moments that divide time into, really, what came before” and after, President Donald Trump said at a 9/11 remembrance in Washington this week. The Republican, who was in his native New York on Sept. 11 and has often recounted his memories, plans to attend the Pentagon's anniversary ceremony Friday.

Vice President JD Vance is expected at the observance at the National Sept. 11 Memorial in New York, while other administration officials are headed to the Flight 93 National Memorial in Pennsylvania.

Planned remembrances extend far beyond the attack sites, from beams of light projecting from New Hampshire's Mount Washington to a stair climb at Mississippi State University's football stadium to a ceremony at Honolulu's 9/11 memorial.

Traditionally, there are no political speeches at the New York commemoration, where relatives read all the victims' names, punctuated with moments of silence at key points in the attack timeline. For the first time, this year's ceremony will add a silent moment to honor people who were exposed to the clouds of toxic dust released by the twin towers’ fiery collapse and have since died of cancer and other illnesses. Questions remain about how many people developed health problems linked to the dust.

It's a reminder of how the attacks' long shadow has reached into many corners of life in the U.S. and beyond.

The U.S.-led global war on terrorism included invasions of Iraq and Afghanistan — the latter Washington's longest war — and detentions and harsh interrogation of terror suspects in an international network of secret CIA prisons. The U.S. military found and killed al-Qaida leader Osama bin Laden in Pakistan in 2011, but accused 9/11 mastermind Khalid Sheikh Mohammed still awaits a trial 23 years after his capture.

The attacks changed U.S. air travel, prompted new federal surveillance and intelligence-gathering powers and banking regulations, and generated ongoing debate over the balance between security and freedom. The Department of Homeland Security, many state anti-terrorism laws and billions of dollars in state and local counterterrorism funding all are post-9/11 creations.

So, too, is the culture of individual vigilance summed up by the slogan “ if you see something, say something.”

Sept. 11 generated a wave of patriotism that propelled some Americans to join the military, fire departments, police forces or other public agencies. But amid the national unity that many remember, the attacks also fanned mistrust, prejudice and hate crimes directed at Muslims.

In the quarter-century since, Muslim Americans have played a growing role in public life from statehouses to Congress to New York City Hall, where Zohran Mamdani is the city's first Muslim mayor. Yet he is facing some criticism for planning to attend the anniversary ceremony at ground zero, something his predecessors have done for years.

Some complaints came from Republican ex-Gov. George Pataki and 9/11 victims’ relatives, who cited among other things past remarks that some of Mamdani's political associates have made about the attacks. Former Mayor Rudy Giuliani, a Republican, also inveighed against Mamdani attending.

Mamdani, a Democrat, responded this week that he loves the city and country and wants the anniversary to focus on victims' families, first responders and New Yorkers who helped one another after the attacks, which he called a “horrific act of terror.” The 34-year-old mayor was an elementary school student in New York on 9/11.

Sept. 11 isn't a federal holiday, but Congress has designated it both Patriot Day and a National Day of Service and Remembrance.

“One appropriate way to remember is by serving,” says Jay Winuk, who lost his brother Glenn Winuk and then co-founded the volunteer organization 9/11 Day with friend David Paine. The group helps people find meal-packing and other volunteer opportunities and this year arranged for dozens of Times Square billboards to pause their advertising at 9:11 a.m. Friday.

Instead, they will simply display the time.

Phillip Flood, 48, watches as the Tribute in Light is tested over the skyline of lower Manhattan, Wednesday, Sept. 9, 2026, in Jersey City, NJ. (AP Photo/Adam Gray)

New York City mayor Zohran Mamdani, center, speaks to FDNY commissioner Lillian Bonsignore, right, during a memorial to commemorate the 25th anniversary of the 9/11 attacks, Wednesday, Sept. 9, 2026, in the Staten Island borough of New York. (AP Photo/Pamela Smith)

Members of the FDNY march with flags during a memorial to commemorate the 25th anniversary of the 9/11 attacks, Wednesday, Sept. 9, 2026, in the Staten Island borough of New York. (AP Photo/Pamela Smith)

An American flag flies, with the lower Manhattan skyline in background, Wednesday, Sept. 9, 2026, in Jersey City, NJ. (AP Photo/Adam Gray)