Pope Benedict XVI has led Christmas Eve mass at St Peter's Basilica in the Vatican. The ceremony began at 10 pm (2100 GMT) instead of the traditional midnight start time.
The schedule was changed at the Vatican years ago to let the pontiff rest before he is deliver a Christmas Day speech hours later from the basilica's central balcony.
Performers dressed as Santa and his reindeers took part in an unusual annual event at the foot of the Woodrow Wilson Bridge, which connects Washington and Maryland in the US.
The show featured a water-skiing Santa, flying elves, and Frosty the Snowman.
US Vice President Joe Biden has posted a picture on his Twitter account wishing people a "happy and safe holiday season".
President Obama and First Lady Michelle Obama recorded their Christmas message over the weekend, thanking America's troops and their families for their service.
Pope Benedict XVI celebrated a late Christmas night holy mass at St. Peter's Basilica in Rome to mark the nativity of Jesus Christ.
Pilgrims, tourists and Romans gathered to watch the Pope light a Christmas peace candle from the windowsill of his private studio and witness the inauguration of a Nativity scene.
Hundreds of Catholics have gathered at the Russian capital for the Christmas Eve service this evening, hosting the Nativity in Moscow. Although Russia Orthodox believers mark the birth of Jesus Christ on January 7, many are celebrating tonight.