In the United States, President Bush issued a Christmas message for his country's troops just days after an attack on a U.S. military hall in the Iraqi city of Mosul killed 14 U.S. service members as well as eight others.
"In Afghanistan, Iraq, and elsewhere, these skilled and courageous Americans are fighting the enemies of freedom and protecting our country from danger," Bush said.
Britain's Queen Elizabeth II urged religious and cultural tolerances in multicultural Britain in her traditional Christmas message, broadcast on television and radio.
"Religion and culture are much in the news these days, usually as sources of difference and conflict, rather than for bringing people together. But the irony is that every religion has something to say about tolerance and respecting others," she said.
The queen also praised Britain's troops overseas.
Spanish King Juan Carlos used his televised Christmas address to pay tribute to the victims of the March 11 train bombings. The king said relatives of the 191 people who died in Spain's worst terrorist attack had his and his family's "deepest affection and understanding."
Fear of violence marked this year's Christmas festivities from Indonesia to Iraq.
Only a few Christians showed up to celebrate Mass in Baghdad's churches because of fears Islamic militants could launch attacks.
In Indonesia, tens of thousands of police stood on guard at packed churches in Jakarta, as Christians celebrated Christmas amid warnings that terrorists linked to al Qaeda planned attacks in the world's most populous Muslim nation.
The Christian minorities in Muslim-majority Pakistan and predominantly Buddhist Sri Lanka, where churches have come under attack, also celebrated with police on alert. Authorities also guarded churches in Muslim-dominated Bangladesh. No trouble was reported.
Gang violence cast a pall over Christmas in the Honduran city of San Pedro Sula, where two days earlier. In a message left on the bus windshield, the gunmen promised more violence, saying: "People should take advantage of this Christmas because the next one will be worse."
In the Haitian capital Port-au-Prince, after yet another year of endemic poverty and political upheaval, many poor Haitians spent Christmas Day like any other: trying to eke out a living.
"I can't celebrate when no one is coming to buy and the country is in such bad shape," said Rosana Suafet, 26, grilling chicken to sell on the roadside. "There used to be a festive ambiance, now things are paralyzed. Now there's shooting downtown all the time and people are afraid."
But festivities were lighthearted in other corners of the globes. Australians in bikinis and Santa suits took their parties and Christmas barbecues to the beach. And in London, Madrid and Paris, the streets were nearly empty as families stayed home for their traditional Christmas dinners.
In Taiwan, a Frenchman who calls himself "Spiderman" marked the day with a daredevil skyscraper climb. Alain Robert, 42, made it to the top of the 101-story Taipei 101, the world's tallest building.
At the Vatican, thousands — many cheering and waving flags — flocked to St. Peter's Square to hear
The pontiff, speaking haltingly, shared his fears about the violence in Iraq, Sudan and other hot spots, and expressed hope that peace-building efforts would bring a brighter future.
"Babe of Bethlehem, Prophet of peace, encourage attempts to promote dialogue and reconciliation. Sustain the efforts to build peace, which hesitantly, yet not without hope, are being made to bring about a more tranquil present and future for so many of our brothers and sisters of the world," John Paul said.
Hundreds of worshippers marched through the streets of the Beit Sahur village in the West Bank, holding candles and singing.
In Bethlehem, the traditional birthplace of Jesus Christ, a .
— a change from previous years, when Israel prevented the late Palestinian leader Yasser Arafat from attending out of fears that he would advocate violence.
Latin Patriarch Michel Sabbah, the senior Roman Catholic official in the Holy Land, called on Israelis and Palestinians to put violence behind them.
"Our situation continues to be a situation of conflict, violence, insecurity, fear, military occupation, the wall of separation, of imprisoned cities and demolitions," he said at St. Catherine's Church adjacent Manger Square.
"Palestine and Israel must conquer the evil of violence ... and give birth to a new society of brothers and sisters in which no one controls the other, no one is occupied by the other, no one causes insecurity for the other, no one takes liberty from the other," he said.
Abbas, a Muslim, said: "We ask God and wish that all the religions in this country will live in peace and security. I hope next year will be much better than the previous ones."