From a dusty embassy compound in Afghanistan to London's cathedrals and mosques, millions around the world gathered Wednesday to remember those who died in the Sept. 11 attacks and to offer prayers for peace and tolerance.

At London's St. Paul's Cathedral, 3,000 white rose petals fluttered down from the dome — one for each victim who died last Sept. 11.

A cellist played a Bach suite and the congregation of 2,000 remained silent as the petals fell. Moments earlier, they joined people across Britain and around the world in observing a moment of silence at 1:46 p.m., the time in London at the moment the first hijacked jet struck the World Trade Center last year.

Religious leaders of all stripes condemned the attacks

"No situation of hurt, no philosophy or religion can ever justify such a grave offense on human life and dignity," Pope John Paul II said at his weekly audience at the Vatican.

At London Central Mosque, Muslim leaders offered Quranic prayers for peace, justice and tolerance.

Around the world, it was a day of simple, heartfelt gestures. In Sydney, Australia, thousands of motorists turned on their headlights at 8:46 a.m. as a mark of respect for those who died.

Cities around the globe paused for moments of silence, while candles were lighted and flowers laid outside U.S. embassies from Copenhagen to Moscow to Manila.

In Paris, two powerful beams of light were projected into the sky Tuesday to honor the memory of the victims — a project to be repeated Wednesday night.

Beginning with choirs in New Zealand and Japan, 180 singing groups in 20 time zones began a "Rolling Requiem," singing Mozart's masterpiece.

U.S. researchers at the South Pole also played the music at their isolated base.

Political leaders expressed their sorrow and solidarity.

"France knows what it owes America," French President Jacques Chirac told a ceremony at the U.S. ambassador's residence in Paris. "The French people stand with all their hearts at the side of the American people."

Russian President Vladimir Putin phoned President Bush to express his condolences.

"In Russia, they say that time cures, but we cannot forget. We must not forget," Putin said, according to portions of the conversation released on Russian television.

European Union leaders expressed their sorrow at the attacks and said they would stand "side by side" with the United States.

"The European Union will not slacken its resolve to contribute to the international community's fight against terrorism," leaders of the 15 EU nations said in a statement.

In Afghanistan, a country battered and transformed by the events of Sept. 11, soldiers and diplomats unveiled the site where a piece of the World Trade Center was buried under the flagpole at the U.S. Embassy, as a bugler played taps and the Stars and Stripes was lowered to half staff.

A steel-gray marble headstone marked the resting place of the remains brought from the ruined towers by a Marine from New York. Inscribed on it: "We serve because they cannot."

"My fear is that people will start to take things for granted, forget about it. "That some kind of amnesia starts to set in," said Lt. Kyle Aldrich, a 27-year-old New Yorker who had worked on Wall Street and joined the Marines after losing friends in the attacks.

Protesters gathered, too. In Bangkok, about 70 people including Thai monks and children held a peaceful protest outside the U.S. Embassy against U.S. military operations in Afghanistan and a possible attack on Iraq.

In the Philippine capital, Manila, supporters and opponents of the U.S. global war on terror held separate rallies to express sympathy for victims of last year's terrorist attacks.

Not all saw the day as a time to mourn.

In Iraq, the state-owned Al-Iktisadi newspaper covered its front page Wednesday with a photograph of a burning World Trade Center Tower and a two-word headline in red: "God's punishment."

"Events like Sept. 11 are sad but it is an opportunity for the American people to feel what bombing could do to nations," said Ali Ahmed, a 47-year-old who owns a Baghdad stationery shop.

Fear of a new terrorist attack overshadowed some memorials. Citing "credible and specific" threats, some U.S. embassies in Asia, Africa and the Middle East were closed, and U.S. military bases and embassies in Europe enforced tightened security.

Authorities in Turkey were told that militants linked to Al Qaeda might be planning poison gas attacks. Australian travelers in southeast Asia were warned following a threat to that country's interests in East Timor.

In Germany, police searched a Hamburg Islamic center after a tip that an Egyptian man staying at a guesthouse there was planning an explosives attack. Police said they found no evidence of terrorist activities.

But the threats often paled before the need to gather in remembrance.

"I spent a year studying in the U.S. — and it's not someone else's problem," said Megumi Hirokawa, an 18-year-old college student who attended a small, quiet ceremony outside the U.S. Embassy in Tokyo.

Speakers in Nairobi, Kenya spoke of the 1998 U.S. Embassy bombings in Kenya and Tanzania during their memorial. Those blasts killed 231 people — including 12 Americans — and wounded more than 5,000.

"Kenya was the victim of a terror attack," said Kenyan Health Minister Sam Ongeri. "Kenyans can sympathize with the victims of Sept. 11."

Canada held a ceremony at the airport of the tiny town of Gander on Newfoundland island, a facility that became the symbol of the country's assistance to a neighbor in need.

When the United States closed off its airspace following the attacks, Canada immediately gave permission for diverted flights to land at its airports.

Thirty-eight planes landed at the Gander airport — Newfoundland is the country's easternmost point — and almost 7,000 travelers stayed for days in the small towns of the remote region.

On Wednesday, passengers and air crew who had been stranded there returned to say thank you, joined by Canadian Prime Minister Jean Chrétien and U.S. Ambassador Paul Cellucci.

"Out of this horror came for me the realization that no matter how much evil there is in the world, there are people who are great and wonderful and that evil will never win out," said Nicholas Dobi, a Continental Airlines pilot.