From China to New York, people placed bets, tied the knot, made a wish and some were even extra cautious.
Friday marked the 11th day of the 11th month of 2011. Around the world, people celebrated the triple convergence of 11s with a splash.
Some 1,000 ethnic Chinese couples exchanged vows across Malaysia on a date viewed as auspicious and romantic. In China, a special "1111" train started at 11:11 a.m. on the No. 11 line in Shanghai.
"The numbers rhyme with one husband, one wife and one soul in Chinese and signifies a marriage that would last a lifetime," said nurse Pua Kim Giok, 25, who tied the knot with engineer Lee Chin Siong, 27. They were among 460 couples who got married at the popular Thean Hou Temple in Kuala Lumpur.
Not everyone was smiling, however.
Egypt's antiquities authority closed the largest of the Great Pyramid of Giza following rumors that groups would try to hold spiritual ceremonies on the site at 11:11.
The authority's head Mustafa Amin said in a statement Friday that the pyramid of Khufu, also known as Cheops, would be closed until Saturday morning for "necessary maintenance."
The closure followed a string of unconfirmed reports in local media that unknown groups would try to hold "Jewish" or "Masonic" rites on the site.
Amin said all reports of planned ceremonies at the site were "completely lacking in truth." The rest of the complex, which includes two other large pyramids, numerous tombs and the Sphinx, and is one of Egypt's biggest tourist attractions, remained open Friday, though security appeared to be heavier than usual.
In the U.S., the Trump Taj Mahal in Atlantic City, N.J., was planning drawings every 11 minutes for up to $1,111.
In Las Vegas, Clark County Clerk Diana Alba got ready for an onslaught of weddings. She was expecting the number of couples to surpass the crowd on 08/08/08 and equal the throng on 10/10/10. It may not, however, reach the turnout seen on July 7, 2007 - a date that consists of three lucky sevens.
"That was like the granddaddy of all dates," Alba said.
Bryan Savage of Oklahoma City was among those tying the knot on 11-11. He said the number 11 is meaningful to him and his fiancee, Tara Melton, because his birthday is in November and they met in November.
"It's just kind of cool and we didn't really want Valentine's Day or a holiday, but we just wanted something memorable," he said.
Plus, he said, it will be easier to remember his anniversary.
In Des Moines, Iowa, Dr. Ross Valone, an obstetrician-gynecologist, will refund any fees he collects from delivering babies Friday. In Bellevue, Wash., Jason Brown planned to open his new grocery store at 11:11 a.m.
Vikki MacKinnon, a numerologist in Calgary, Alberta, said she expected the day to be a "cosmic wake-up call."
"Eleven is a number of illumination and enlightenment, a number of insight, blinding flashes of the obvious, and a number of transformation," she said.
The Chinese have always had a fascination with number sequences.
And in a country where ages of first marriages are creeping upward, the 11/11/11 date represents six "bare sticks," a term for bachelors in Chinese.
And there are now more of them, with housing prices, focus on jobs and growing independence of young women meaning people are getting married later.
"It's just difficult for men to afford the housing prices nowadays, and traditionally in China that is the responsibility of the man his family. I feel a lot of pressure from this," said Zheng An, a 26-year-old employee at a solar company in Shanghai.
Associated Press writers Michael Crumb in Des Moines, Iowa, Tim Talley in Oklahoma City, Geoff Mulvihill in Haddonfield, N.J., Eileen Ng in Kuala Lumpur, Malaysia, Fu Ting in Shanghai, and Ben Hubbard in Cairo contributed to this report.